Sage Journals: Discover world-class research

Abstract

There have been ongoing debates about whether outlaw motorcycle groups (OMCGs) are similar to mafia organizations. The current study examines to what extent and how Dutch OMCGs, specifically the Hells Angels, Satudarah, and No Surrender, resemble mafias. The study is based upon a review of the relevant academic and gray literature, criminal investigations against members of the above-mentioned OMCGs (N = 52), and court judgments in criminal (N = 52) and civil law cases (N = 9). Against the backdrop of Paoli’s mafia framework, the analysis shows that, despite similarities in structure and culture, Dutch OMCGs radically differ from mafia organizations in the aims they pursue and the range of activities they engage in, and particularly in their claim and ability to exercise a political dominion, enter in power-sharing agreements with state representatives and achieve popular legitimacy. Based on these findings, the article emphasizes the importance of comparative analyses of so-called organized crime actors for theory-building as well as their policy relevance to prevent misconceptions in society and among policymakers and to enable the adoption of appropriate policy measures.

Keywords

Criminal organizations mafia organizations organized crime outlaw motorcycle gangs

Introduction

The outlaw motorcycle group (OMCG) subculture originated in the United States during the interwar depression period when groups of young men rode their motorcycles from state to state in search of employment. Since then, various small, unorganized clubs have grown into international organizations with hundreds of local chapters, or subgroups, organized according to a military-style hierarchy and with their club logo's registered official trademark (von Lampe and Blokland, 2020). Although OMCGs have not always been perceived as a threat, nowadays members of these clubs are increasingly associated with deviant behavior and are considered a security risk due to their anti-establishment attitudes. In Canada, Australia, and several European countries, OMCGs have even developed into a significant public order and (organized crime problem (Bjørgo, 2017; Lauchs et al., 2015; Morgan et al., 2020). These countries have experienced major incidents involving OMCG members, including serious inter-club violence with—at times—innocent bystanders as victims (Ayling, 2017; Jahnsen, 2018). Like a growing number of criminal organizations and other groups whose members engage in profit-making crime (see Paoli et al., 2024), OMCGs, too, have been increasingly said to resemble mafia organizations (or, for short, mafias) to stress the threat they pose to their host societies (e.g., Endedijk and Roox, 2022).

The aim of the current study is to empirically examine to what extent Dutch OMCGs are similar to mafias, furthering the comparative research started by Paoli since 2020 (Paoli et al., 2024; Reuter and Paoli, 2020). Prior research on OMCGs finds ample variation across different clubs (Blokland et al., 2014, 2017a, 2017b, 2020). Therefore, instead of examining all OMCGs, this study particularly focuses on the three most prominent Dutch OMCGs: Hells Angels, Satudarah, and No Surrender. These OMCGs were subjected to intensive administrative and criminal law measures and have recently been irreversibly banned based on civil law procedure (Geurtjens et al., 2018; Koornstra et al., 2019; Van Ruitenburg, 2020; Van Ruitenburg et al., 2024).¹ This study uses a literature review, criminal investigations filed against members of three Dutch OMCGs, and court judgments regarding these criminal investigations and the civil bans.

The theoretical vantage point for the study is Paoli's mafia framework (Paoli, 2020). This theoretical framework distinguishes seven characteristics of a mafia organization: longevity, large size, formalized and complex structure, cultural apparatus, multifunctionality, goal of political domination and long-standing ability to provide governance services, and legitimacy and power sharing with government authorities. The proposed analyses will not only provide detailed insight into the ways different Dutch OMCGs function but will also allow us to compare the workings of OMCGs and mafias.

This article has the following structure. First, we provide an overview of the seven characteristics of Paoli's mafia framework. Second, we briefly discuss our sources and methods Third, we present the main results: for each characteristic of Paoli's mafia framework, we consider to what extent it applies to the three selected Dutch OMCGs. In the conclusion, we elaborate upon the key findings, provide suggestions for future research, and discuss the policy implications of the current study.

Theory

Paoli's (2020) mafia framework, which serves as the theoretical framework for this study, emerged from the comparison of the five organizations everyone agrees constitute mafias: the Calabrian ‘Ndrangheta, Chinese Triads, Japanese Yakuza, and the Sicilian and American Cosa Nostras (see also Catino, 2019). Whereas Gambetta (1993), in his seminal work on the Sicilian Cosa Nostra, singled out one function—the provision of private protection—as typifying of mafias, Paoli rejects a simple functionalist characterization and, in a dialogue between theory and empirical data analysis inspired by Layder's (1998) adaptive theory, has identified seven common traits. Four of them are internal to each organization and three are external, that is, they concern the relationship between each mafia and the surrounding society, including the state. Although the five mafias have distinct history and evolution, Paoli (2020) shows that each possesses these traits.

Internal traits

Longevity. The ﬁve iconic maﬁas have all existed for at least a century, with the Triads and Yakuza going back to the 17th and 18th centuries, respectively (Kaplan and Dubro, 1987; Murray, 1994). Mafias’ premodern roots influence their structure and culture. They also probably explain why mafias, with few exceptions, recruit only males into their ranks. Their longevity has been a source of power since it creates an expectation of survival and enhances reputation and thus the capacity to intimidate by threat alone.

Large size. All ﬁve maﬁas have had in their histories at least a few thousand members for several decades. The Triads and Yakuza had more than 230,000 and 180,000 members, respectively, at their peaks (Morgan, 1960; National Police Agency, 2018).

Formalized and complex structure. The five mafias have formalized and complex internal structures, which entail ruling bodies within each unit, or group, and often also within the consortia. This structure creates a clear-cut separation between members and non-members and, in a Weberian perspective (Weber, [1921] 1978: 48), makes them true organizations, distinguishing the mafias from looser entities/syndicates.

Elaborate cultural apparatus. Mafia organizations possess a complex set of cultural codes, rituals, norms, and sanctions through which they create a collective identity, justify their existence, and aim to generate a lifelong commitment, a new identity, and fictive kinship ties among their members.

External traits

Multifunctionality. Throughout their existence mafias have carried out a variety of functions, aiming at both money and power, engaging in numerous illegal and legal activities and usually granting their members considerable autonomy in their money-making activities. With the possible exception of the American Cosa Nostra, proﬁt maximization is not even today their exclusive or even their main aim.

Goal of political dominion and long-standing ability to provide governance services. Maﬁa organizations are different from illegal enterprises and from other criminal organizations because they claim to exercise a local political dominion that extends beyond their members and collaborators. They also deliver certain governance services, particularly related to settlement of disputes and provision of personal security.

Popular legitimacy and power sharing. With their claim to exercise a political dominion, maﬁas have long enjoyed a considerable degree of popular legitimacy and have entered de facto, or sometimes even ofﬁcial, into power-sharing arrangements with local state institutions. No other organized crime actors have enjoyed such long-standing legitimacy from both the communities within which they operate and local state authorities.

Given these traits, mafias are distinct from other organized crime actors. They constitute an exception, rather than a model. Most organized crime actors merely consist of (usually short-lived) enterprises supplying fully or partially criminalized goods and services or committing frauds and a few other predatory crimes with the exclusive aim of profit maximization (e.g. Bouchard and Morselli, 2014; Reuter, 1983).

Current study

The aim of the current study is to explore to what extent three different Dutch OMCGs share the above-mentioned characteristics of mafia organizations. Existing OMCG research tends to focus on the OMCG subculture as a whole, without differentiating between different types of OMCGs (Blokland et al., 2019; Klement, 2016; Morgan et al., 2020). Nonetheless, there are sound reasons to assume that the extent to which Dutch OMCGs resemble mafia organizations may differ among OMCGs. The origins of OMCGs and the types of individuals joining OMCGs vary from club to club, for example, in terms of demographic and criminal career background (Blokland et al., 2017b, 2019). Therefore, instead of examining Dutch OMCGs as a homogeneous subculture, this study uses the theoretical framework of Paoli (2020) to systematically analyze the three most prominent Dutch OMCGs: Hells Angels, Satudarah, and No Surrender. The comparative analysis is also enhanced by the fact that these three OMCGs considerably diverge from each other in terms of origin, composition, and activities.

The study is based on a combination of different qualitative data. In addition to a review of the academic and gray literature, we have analyzed 52 criminal investigations in which at least one member of the Hells Angels, Satudarah, or No Surrender was accused of involvement in crime, and 61 court judgments resulting from the 52 criminal investigations and nine civil bans regarding these three clubs.

Data and methods

This study used three data sources. First, we reviewed the current literature on Dutch OMCGs, with a special focus on Hells Angels, Satudarah, and No Surrender. The literature review encompassed the academic literature related to Dutch OMCGs in the period 1980–2024. The year 1980 was chosen as a starting point because the first Dutch OMCG, the Hells Angels, entered the Netherlands only in the late 1970s (Van Ruitenburg, 2020). The review also included gray literature, such as publicly available police and media reports. We retrieved the academic literature through primary databases, such as Scopus, Web of Science, and International Bibliography of the Social Sciences (IBSS). The search terms were focused on (1) OMCGs (e.g. outlaw motorcycle gang OR outlaw motorcycle club OR outlaw biker) and (2) the Netherlands (e.g. Dutch OR the Netherlands). The gray literature was found by scanning Dutch government websites and Delpher—an online archive for newspaper articles. The search terms in Delpher were specifically focused on the three Dutch OMCGs examined for this study. The literature search resulted in 19 academic articles and 10 police (2), or media (8) reports on Dutch OMCGs deemed relevant and selected for the present study (selected documents are specified by an asterisk in the reference list).

Second, our empirical data consisted of 52 closed criminal investigations into members of Dutch OMCGs. In each case, the criminal investigations analyzed contained the results of all policing activities that were deployed, such as wiretapping, interrogations with suspects, and observational evidence. The investigations were completed by the police in the period between 2012 (the start of the Dutch multi-pronged, whole-of-government approach) and 2018.

The starting point for this study was a list of 60 criminal investigations in which at least one member of a Dutch OMCG was allegedly involved. These criminal investigations concerned six Dutch OMCGs and were used in a previous study examining the role of OMCGs as organizational entities in members’ criminal behavior (see Van Deuren et al., 2022c), for a more detailed description of the selection procedure). For this study, we used only investigations in which at least one member of the Hells Angels, Satudarah, or No Surrender was involved. This selection resulted in 52 criminal investigations that were retained, of which 34 referred to Satudarah, nine to the Hells Angels, and nine to member(s) of No Surrender. One criminal investigation was related to both members of Satudarah and members of No Surrender. The criminal investigations included cases in which suspects were accused of being involved in different criminal acts, such as drug offenses (public) violence, and threats. The investigations were previously systematically examined in the study of Van Deuren et al. (2022c), who considered several topics, including the composition and structure of the criminal networks and the contacts with the (internal and external) environment on the basis of an analytical framework developed in the context of the Dutch Organized Crime Monitor (Kleemans, 2014). For this specific study, we especially focussed on the structure of the criminal network and clubs, rules and sanctions, and the OMCGs’ governance functions. The Dutch Public Prosecution Service and the Ethics Committee of the Vrije Universiteit Amsterdam granted permission for the analyses of the criminal investigations.

Third, we also analyzed the court judgments that were included in 40 criminal investigations and retrieved the judgments concerning 12 other relevant criminal investigations from Rechtspraak.nl.² Furthermore, we also examined nine court judgments resulting from the civil bans against Hells Angels Holland, Satudarah, and No Surrender, because they described in detail each club's structure, rules, and culture.³ In the current study, the description of each case, including the name of the OMCG involved, was based on publicly available data from Rechtspraak.nl.

Results

Longevity

The three Dutch OMCGs differ considerably in terms of their longevity but are overall younger than mafias. The oldest OMCG is the Hells Angels, which Sonny Barger founded in America (Oakland, CA) in 1948, shortly after the end of World War II and—at the time of this study—has charters in 62 different countries worldwide (www.hellsangels.com). The club made its way to the Netherlands in the mid-1970s when a group of young men, known as the Kreidlergroup East, who rode mopeds and motorcycles, became inspired by the Hells Angels. In 1978, with approval of the American mother charter, this group established the first Dutch charter of the Hells Angels in the city of Amsterdam (Van Ruitenburg, 2020).

The eighties and early nineties witnessed the establishment of several other Dutch OMCGs. In 1990, 12 years after the establishment of the first Dutch Hells Angels, Satudarah was founded by nine friends, most of whom were of Moluccan descent (The Maluku islands, or Moluccas, are a former Dutch colony, which is now part of Indonesia). From 2011 onwards, Satudarah started establishing chapters outside the Dutch borders, primarily in Germany and Denmark. It hence became the second Dutch OMCG—after the Hells Angels—with a transnational spread.

No Surrender is by far the youngest of the three, as it was established in 2013 by a former president of Satudarah. The club has been from the outset multicultural, as stressed by the founder of No Surrender himself: ‘I have a club that is open to motorcycle enthusiasts from all cultures. Whether it is Turks, Moroccans, football hooligans, gypsies or Antilleans, everybody is welcome' (Kamp, 2014). Soon after its foundation, No Surrender started establishing chapters abroad, including in Belgium, Germany, and Spain (Blokland et al., 2017b).

The OMCGs analyzed in this study thus have been around in the Netherlands for about 10–45 years. Compared to mafia organizations that have been in operation in Southern Italy since the 1860s and in Asia since at least the 18th century, this is a relatively brief period of time. In particular, Satudarah and No Surrender have only been active for about 30 and 10 years, respectively. However, the Hells Angels, which were founded in the United States in 1948, are only a few decades younger than the American La Cosa Nostra, which consolidated in the 1920s as an offspring of the Sicilian mafia (see, for details, Paoli, 2020). Despite their much more limited longevity, the three Dutch OMCGs exclusively enroll men, much like the mafias (Blokland et al., 2017b, 2019; Van Deuren et al., 2022b).

Large size

Much like the mafias, OMCGs are consortia composed of multiple units and enrolling a significant number of members—traits that clearly distinguish them from the small and fairly ephemeral gangs that are responsible for the bulk of organized crime activities in Western countries. Unlike the Yakuza, Dutch OMCGs do not hold publicly available official membership lists, making the total number of their members unknown. The total size of the OMCG population is generally estimated based on the number of known chapters and the average number of members per chapter. Prior (international) research suggests that OMCG chapters typically consist of a minimum of six and a maximum of 25 members (Blokland, 2019).

Based on the total number of 18 chapters reported in 2016, the estimated number of Hells Angels members in the Netherlands ranges from 108 to 450 (Blokland, 2019). Recent qualitative research in which current members of the Dutch Hells Angels were interviewed, shows that approximately 240 individuals were actively affiliated with the club in 2022 (Van Deuren et al., 2024b). Internationally, on the club's official website, the Hells Angels report a total of 475 charters worldwide. This would lead to a total membership estimate varying between 2850 and 11,875 members.

Satudarah expanded from nine chapters in 2011 to 36 chapters in 2016 (Blokland et al., 2017b). The estimated number of members of Satudarah in the Netherlands in 2016, therefore, ranged between 216 and 900. Internationally, the criminal investigations show that in 2016, Satudarah reported to have 84 chapters in 21 different countries, including Indonesia, Germany, and Spain, leading to a total membership estimation of 504–2100.

Since its foundation, No Surrender has quickly expanded to become one of the largest OMCGs in the Netherlands. In 2019, it listed 30 Dutch chapters on its website, leading to an estimated membership range of 180–750. Internationally, police and governmental reports indicate that No Surrender has 14 chapters in foreign countries, leading to a total membership estimation of 264–1100.

In terms of membership, the Hells Angels, Satudarah, and No Surrender are considerably smaller than the mafias were at their peak, particularly the Asian ones. However, their size seems comparable to the current membership of the Sicilian and American Cosa Nostras. Despite the lack of official figures, these two mafias are each currently unlikely to have more than 1000 ritually affiliated members (Paoli, 2020). Whereas mafias, except for the Chinese Triads (Chin, 2014), have not expanded (much) outside their traditional strongholds; the three OMCGs have a broad international spread.

Formalized and complex structure

Much like the mafias, the three OMCGs have formalized, complex internal structures that include ruling bodies in each unit of the consortia. OMCGs can hence be considered organizations in a Weberian perspective (Weber, [1921] 1978: 48). As the mafias, though, they have a segmentary structure, granting considerable autonomy to the single chapters (called charters in the Hells Angels) composing each OMCG.

Much like the units composing the mafias, each chapter of the three OMCGs has an elaborate internal structure with different and well-specified roles for its members. The leadership hierarchy of an OMCG chapter generally consists of a president, vice-president, secretary, treasurer, and sergeant-at-arms, followed by full-patched members, and men who are not yet full-patched members (prospects and hang-a-rounds). Much like the Cosa Nostras used to do, the Hells Angels assign these command positions through frequent elections (Catino, 2019: 147). As the ‘Ndrangheta and the Asian mafias, Satudarah also has a national leadership and advisory group called the Nationals, which include roles such as Malessy's (founding, most senior members), Kapikane's (who have an advisory role), and Nomads (members who are undergoing a training for the role of Kapikane).

Mafias as well as OMCG members are expected to obey without hesitation the orders of those holding command positions within their groups, if these orders concern group-related matters. In the past, Italian mafia members were required even to risk their life or freedom, if the boss of their units asked them, for example, to commit a murder. Dutch criminal investigations show that Satudarah's chapter leaders also claim control over their (future) members’ club-related activities. In a newspaper interview, an office bearer of Satudarah stated: ‘We are portrayed as a dictatorship, and that is indeed true, as the Malessy's and Kapikane's determine the policies of the club’ (De Hoogh, 2014). In contrast, the Dutch Hells Angels seem to have a less controlling, more ‘democratic’ leadership style, as suggested also by the practice of holding frequent elections. However, as in the mafias, power relations are inherently unstable, with upcoming members sometimes challenging the holders of formalized ruling positions and elections merely certifying equilibriums established beforehand. Moreover, in all groups, members’ profit-making (legal or illegal) activities are considered private matters, outside the scope of the group leaders’ authority (see also multifunctionality).

The three Dutch OMCGs have not established formal higher-level coordinating bodies within their consortia, such as the commissions in the two Cosa Nostras and the so-called crimine in the ‘Ndrangheta. Even within several mafias, though, these higher-level coordinating bodies constitute relatively recent additions to the segmentary structure—and have proven to be fragile. The American Cosa Nostra's commission was famously established in the 1930s, the Sicilian Cosa Nostra's commission for the province of Palermo, where most mafia families were settled, was set up in the 1960s and the regional commission for all Cosa Nostra families only goes back to the 1970s. The ‘Ndrangheta's coordinating body, the crimine, is even more recent, as it was established in the 1990s. Under the growing pressure of law enforcement agencies, the Sicilian Cosa Nostra's commissions have been disbanded since the 1990s, while the American Cosa Nostra commission is a shade of its former self if it is convened at all. In Hong Kong, too, the Triads’ hierarchical structure has been radically simplified and some Triads themselves have even ceased to exist. Only the ‘Ndrangheta's crimine, along with the coordinating bodies of the main Yakuza consortia, such as the Yamaguchi Gumi, which are not yet fully criminalized, are still operative (Paoli, 2020).

While no formal coordinating body was established within any of the three selected OMCGs, in 1996 the eight OMCGs active in the Netherlands at the time set up the so-called Council of Eight. This consultative body has also been short-lived, as it was disbanded in 2013 when several OMCGs withdrew. Much like the Cosa Nostra's and Ndrangheta's commission, the Council of Eight was established with the primary task of preventing inter-club conflicts, as the Dutch OMCGs were eager to avoid the fights that had shaken Scandinavian OMCGs in the 1990s (Korps Landelijke Politiediensten, 2010). According to law enforcement agencies, the Council of Eight also decided which clubs could identify themselves as ‘MC’ and delineated territories in which each club could operate. It is known that the Sicilian Cosa Nostra's commissions occasionally exercised similar tasks—and probably other mafias’ coordinating bodies have done so, too. Since the dissolution of the Council, Dutch OMCGs and their chapters seem to operate fairly autonomously.

Elaborate cultural apparatus

OMCGs’ cultural apparatus is also as elaborate as that of mafias and is meant to create a collective identity, justify the groups’ existence, and generate fictive kinship ties among their members. Much like mafias, Satudarah and No Surrender stage initiation rituals to formalize the admission of new members. During these initiation rituals, ‘novices’—called hang-a-rounds in OMCGs—walk through a line of club members with their upper body exposed, while being hit with rolled-up leather jackets by fellow club members. One of the criminal investigations indicates that Satudarah members also take a blood oath to become full-patched members of the club. In the Hells Angels, instead, there is no indication of such a formalized initiation ritual.

Comparable to mafiosi, OMCG members must undergo a selection process through which they prove their worthiness for membership and reliability. Unlike mafia members, though, prospective members can already take part in many of their group's activities. In the Dutch Hells Angels, for example, prospective members are socialized into the club's culture by engaging in several club activities, such as running bar shifts, visiting the club's charters, and making (international) motorcycle rides (Van Deuren et al., 2024b). As in the mafias, there are clear inclusion and exclusion criteria for OMCG membership. As in the mafias, no women are allowed to join the clubs. The criminal investigations also indicate that no police informants (ex-)police officers or problematic drug users are allowed to become a member of the Hells Angels—as in the Southern Italian mafias. With regards to ethnic/regional restrictions, the Sicilian Cosa Nostra, the ‘Ndrangheta, and the American Cosa Nostra, with few exceptions, admit only men of Sicilian, Calabrian, and Italian-American descent, respectively. For a long time, the Hells Angels predominantly consisted of white Dutch males, while Satudarah strongly attracted men of Moluccan descent. Only No Surrender has been from the outset an ethnically heterogeneous group.

Satudarah has the most outspoken ethnic identity and is deeply intertwined with Moluccan culture, including the (ex-)military background of many Moluccan families. After World War II, many Moluccans fought in the Dutch colonial army (KNIL) during the Indonesian War of Independence. They were forced to migrate with their families to the Netherlands, with the unfulfilled promise that they could return to their own free Moluccan state. Connecting to this past, Satudarah founders called themselves the ‘heirs of the Moluccan warriors’ and a so-called Alfur warrior is depicted on the club's logo, which also mentions the name Maluku. Testifying to the intention of creating fictive kinship ties, the name ‘Satudarah’ means ‘one blood’ in Indonesian Malay.

As the OMCGs were not until recently banned, they could openly deploy their cultural apparatus to strengthen their collective identity and parade their power, using logos, leather jackets with specific colors, and motorbikes of specific brands. The Hells Angels have even copyrighted their colors and patches to prevent unauthorized use—and in the US they went to court to challenge unauthorized use of their name and logo (von Lampe and Blokland, 2020). Public signs of recognition were extensively used in the past in the ‘Ndrangheta and the Triads, and are still used in Yakuza. With the intensification of law enforcement pressure, though, public signs of recognition have been progressively dismissed in both mafias and OMCGs.

Dutch criminal investigations and court judgments show that all three OMCGs under study enforce the code of silence to prevent members from revealing secrets about the groups’ activities—much like the mafias and other criminal organizations do. At least one Hells Angels charter explicitly states that

any discussions among Hells Angels members [charter name] are considered confidential and shall remain within our group; no information will be disclosed to external parties any discussions among Hells Angels members [charter name] are considered confidential and shall remain within our group; no information will be disclosed to external parties.⁴

Like the ‘Ndrangheta and the Asian mafias, the three selected OMCGs also have written rules. In the Hells Angels, these rules are part of a written codex, commonly referred to as World Rules, which applies to all charters worldwide. The World Rules define admission criteria, regulate the transfer of members between charters and, above all, establish how a Hells Angels member is supposed to behave.⁵ The OMCG's rules also prescribe the sanctions to be imposed if members do not behave according to the prevailing rules, listing suspension, monetary fines, and expulsion from the club—but no death, which is instead explicitly foreseen as a sanction in the ‘Ndrangheta's and Triads’ codes and has often been practiced in the two Cosa Nostras as well.

Criminal investigations show that the three OMCGs have applied their sanctions on fellow members through so-called bad standing procedures, the most severe punishment in OMCGs. Several criminal investigations and court judgments show that Satudarah and No Surrender members have been expelled from the club in bad standing with violence:

A member of Satudarah was expelled from the motor club in so-called bad standing. He was accused of not following the club's rules and making negative remarks about the sergeant-at-arms of his chapter. Consequently, the member needed to hand in his motorcycle with a value of € 14,000, to submit the paperwork of his motorcycle, and to pay €5000 to the club. The court judgement of the criminal case indicates that the member was physically assaulted by his fellow club members during the bad standing procedure. Additionally, the member was expected to remain silent about what had been taken away from him and what he had endured during the bad standing.⁶

The cases involving a bad standing procedure indicate that members could be barred from club membership after being caught lying, breaching confidentiality, using the club colors—without permission from the club—to commit violent crime on their own, or otherwise engaging in behavior that could harm the club (Van Deuren et al., 2022c).⁷^,⁸ Interestingly, criminal cases show that sanctions are not only imposed by the OMCG leadership on wayward lower-level members, but at least occasionally also on the latter on their board members, if these have been found to breach the club rules:

The president of a support club of No Surrender was alleged to have embezzled money from the club and posted messages on social media against the club's rules. The president was confronted about his behavior in the clubhouse. He was ordered to hand in his motorcycle and pay a fine of €5000 to the club. Subsequently, three fellow club members got into the car with the president to pick up his motorcycle from a repair shop. Along the way, the president was warned that they would know how to find him if he did not cooperate. When the fellow club members discovered that the motorcycle had not yet been repaired and could not be taken, it was decided that the president would first pay €1000 to the club.⁹

Multifunctionality

The multifunctionality of the OMCGs is more pronounced than the mafias’ in terms of members’ motivation, but it appears more limited, once we consider the activities OMCGs and their members have actually engaged in. According to law enforcement agencies, individuals are attracted to OMCG membership because of the criminal profit-making opportunities group membership can offer them (Landelijke Eenheid, 2014). While this motivation has become more prominent in the mafias, too, it has never been the exclusive one for either set of groups. In neither set of groups, the enhancement of members’ interests has been restricted to criminal activities. Recruits of both mafias and OMCGs were/are also awed by the organizations’ collective identity and promise of brotherhood. In the OMCGs, love for motorcycles and the freedom associated with the outlaw biker lifestyle constitute additional motivations (Van Deuren et al., 2024b; Visscher, 2014). Reflecting these non-instrumental motivations, OMCG members spend a lot of time, just hanging out together in informal settings—just like many mafiosi used to do.

Unlike the mafias, however, Dutch OMCGs have engaged in a more limited number of instrumental activities. The empirical research conducted so far in the Netherlands does not show any involvement of the Dutch OMCGs in the legal economy, except for the legitimate occupations of their members. Many of the latter are known for their engagement in a wide variety of illegal activities, such as violent, property, and drug-related offenses (Blokland et al., 2017b, 2019; Van Deuren et al., 2021, 2022b). With a few exceptions of individual members who seem(ed) to be big players in local Dutch organized crime, however, the criminal investigations do not show evidence of members of the three clubs being responsible for, say large-scale drug shipments. With the exception of the ‘Ndrangheta, mafias today are neither big players in drug trafficking, but the two Cosa Nostras and the Triads played important roles in the past (Paoli, 2020).

As in the mafias, only internal violence (towards fellow (ex-)OMCG members) and external violence (towards rival OMCGs) are organized, as a rule, by the group themselves. For profit-making activities, instead, both OMCG members and mafiosi operate quite autonomously (Paoli, 2020; Van Deuren et al., 2022a). In particular, drug trafficking and money laundering are mostly carried out by individual members on their own behalf, with co-offenders inside and/or outside their respective groups. Furthermore, there is no evidence that Hells Angels, Satudarah, or No Surrender members share criminal profits with their respective club.

Much like mafia members, though, OMCG members benefit from their membership when committing crimes. In both cases, the value added of OMCG or mafia membership is primarily indirect, for instance, because the group may function as a source of criminal information, as a pool of potential co-offenders, or the violent reputation associated with membership of the groups may be verbally or symbolically used by individual members to intimidate victims and witnesses (Blokland and David, 2016).

However, while between 140 and 240 mafia murders were recorded yearly in Sicily and Calabria in the early 1990s (Paoli, 2020), members of the three Dutch OMCGs have engaged in lethal violence much more sparingly. Only a few incidents are known, such as the triple murder of members of the Hells Angels’ ‘Nomads’ charter presumably committed by fellow members of the club and the killing of ‘Haagse Rinus’ by fellow club members of Satudarah. In recent years, though, mafia violence has been considerably reduced. Since 2017 Sicily and Calabria have recorded only a handful of murders yearly and there has hardly been mafia-related violence in the United States, Japan, or Hong Kong (Paoli, 2020).

Goal of political domination and long-standing ability to provide governance services

For this and the seventh characteristic (i.e. legitimacy and power sharing), we find the biggest differences between mafias and OMCGs. If we recall the three governance functions—governance of fellow members, governance of particular (il)legal sectors or areas, and governance of politics (Campana and Varese, 2018; Van Deuren et al., 2024a)—that are often distinguished in the literature, we find that Dutch OMCGs have only been able to exercise the first type (by written rules and a sanction system, see the section on culture), yet, unlike the mafias, have never engaged in the latter two types. While mafias have repeatedly controlled both some criminal and legal markets in their strongholds (Paoli, 2020), there is hardly any evidence that Dutch OMCGs have ever been able to do so. True, according to Bovenkerk and Fijnaut (1996), several leaders of the Hells Angels claimed to govern the sex industry in Amsterdam in the early 1990s. However, none of the criminal investigations analyzed in this study show that the Hells Angels, Satudarah, or No Surrender have been able to govern specific areas or (il)legal sectors in recent years. Unlike the Southern Italian mafias, they have never imposed protection rackets. We only know of a case in which members of a Hells Angels chapter tried to prevent a new tattoo shop from opening. This shop had been set up by the former business partner of a Hells Angels member after leaving the tattoo shop they used to run together.¹⁰

At the peak of their influence, mafias enjoyed extensive contacts with local and even national politicians of their respective countries, including the prime ministers in both Italy and Japan (Paoli, 2000). In the case of the Dutch OMCGs, instead, we find no evidence of governance of politics or even collusion with national or local politicians. Besides a futile attempt by an office bearer of No Surrender to gain a seat in the Dutch House of Representatives with a political party he founded, ‘Rechtdoor’ (Straight Ahead) (RTV Drenthe, 2016), no OMCG member is known to have been involved in politics.

Moreover, despite claiming control over specific turfs, none of the Dutch OMCGs has ever been able to exercise a quasi-political dominion over a specific territory, like the five mafias, with the exception of the American Cosa Nostra, which did in their heydays (Paoli, 2020). Nor have OMCGs ever provided much-needed services to the broader population, such as mediation in case of interpersonal conflicts or the guarantee of property rights because the Dutch state quite competently offers them and is considerably stronger, more effective, and legitimate compared to the state authorities ruling over the areas where mafias first developed.

Legitimacy and power sharing

Providing no useful services to fellow citizens, having had no political power or contacts with politicians, OMCGs have—unlike the mafias—never enjoyed popular legitimacy or shared power with state representatives or authorities. True, several club members have made efforts to improve their reputation in Dutch society. According to media reports, some occasionally engaged in charitable activities, such as selling teddy bears for disabled children, delivering gifts and chocolates to children's hospitals, or collecting food and toys to distribute through Christmas packages for poor families (De Groot, 2015; Franck, 2016; Van Kommer, 2020). While members of the Hells Angels have remained largely silent in the media, members of Satudarah and No Surrender have also used various media platforms to improve their public image. For instance, an office bearer of No Surrender became a (local) celebrity after starring in a documentary on public television in which he gave insight into the club and his private life (called Captain Henk). Despite involvement in charitable activities and public relations campaigns, it seems that OMCGs have never achieved widespread legitimacy in the Netherlands, outside the biker subculture and, in Satudarah's case, the Moluccan community. OMCGs are primarily a blue-collar phenomenon, and, unlike the mafias, their members have never had connections with high-level politicians, governmental officials, or wealthy businesspeople.

There have also never been power-sharing agreements between the Dutch OMCGs and state authorities. Although the three clubs were legal until recently (like other civil associations), from the early 2010s onwards Dutch authorities became convinced that these three and other clubs represented a threat for the Dutch society. The Dutch government adopted a tough, multi-agency strategy, in which various agencies have used administrative, fiscal, and criminal law measures to address OMCGs at the individual and club levels (Van Ruitenburg and Blokland, 2022).¹¹ From 2016 onwards, civil bans were also imposed on specific OMCGs, as these ‘motorcycle gangs disrupt society through intimidation and threats to local governments,¹² and they engage in drug-related nuisances, money laundering, physical violence, and numerous other criminal activities.’¹³ In November 2020, Satudarah MC and two support clubs were banned by the Supreme Court. In 2022 bans were also imposed on Hells Angels Holland and No Surrender.¹⁴ After an irreversible civil ban, members of the clubs can be prosecuted for continuing the activities of a banned organization (Article 140, subsection 2 of the Dutch Criminal Code). Several recent court judgments concluded that wearing clothing of the banned OMCG in public, holding meetings with multiple chapters and members of the banned OMCG, and establishing a new OMCG without sufficiently distancing oneself from the activity of the banned OMCG (i.e. name of the OMCG, club insignia, and members) are punishable by the Dutch Criminal Code (Article 140, subsection 2) (see also Koornstra et al., 2019).¹⁵

Discussion and conclusions

This study aimed to provide insight into the extent to which three Dutch OMCGs—Hells Angels, Satudarah, and No Surrender—resemble mafia organizations. Drawing from the academic and gray literature, criminal investigations of members of these Dutch OMCGs, and court judgments of the criminal investigations and civil law measures, we have compared Hells Angels, Satudarah, and No Surrender to mafia organizations for each of seven typifying characteristics of mafias: longevity, size, formalized and complex structure, cultural apparatus (internal traits); and multifunctionality, goal of political domination and long-standing ability to provide governance services, and legitimacy and power sharing (external traits) (Paoli, 2020; Reuter and Paoli, 2020).

Dutch OMCGs predominantly resemble mafia organizations when it comes to the four internal traits. They have been established more recently than mafias, but the US Hells Angels is only a few decades younger than the youngest mafia, the American Cosa Nostra. The OMCGs under study are all large consortia composed of multiple units and, at their peak, several hundred members. They have formalized and complex internal structures that include ruling bodies in each unit of the consortia. The OMCGs also possess an elaborate culture consisting of rituals, symbols, norms, and sanctions through which they create a collective identity, justify their existence, and aim to generate a lifelong commitment and subordination to the groups’ interests among their members—at the same time as they all leave their members free to engage in their own (il)legal business activities.

Once we consider the external traits, however, the similarities are much more limited. OMCG members report various motivations for enrolling in the clubs, including fairly innocent ones, and the groups and their members engage in multiple (criminal) activities. Unlike the mafias, though, OMCGs or their members have not controlled any major legal businesses or influenced any legal or illegal local markets. The three Dutch OMCGs appear to have never had any undue contact with politicians or government officials, run protection rackets, or exercised a quasi-political dominion over a specific territory. Unlike the mafias, OMCGs have also never enjoyed popular legitimacy (except possibly for pockets of the Moluccan community in the case of Satudarah) or shared power with state representatives or authorities. To sum up, despite similarities regarding internal traits, Dutch OMCGs radically differ from mafia organizations, especially in the aims they pursue and the range of activities they engage in, and particularly in their claim and ability to exercise a political dominion, enter in power-sharing agreements with state representatives, and achieve popular legitimacy.

The weak scoring of Dutch OMCGs on mafias’ external traits calls for a careful interpretation of their similarities with the mafias on the four internal traits. These similarities, in fact, should not be used to conclude that Dutch OMCGs are, or were, powerful criminal organizations. Rather, the large size, formal structure, and elaborate cultural apparatus were made possible by the legal status that OMCGs enjoyed in the Netherlands until a few years ago (just like other civil associations). Except for the predecessors of the Tiandihui in 19th-century Malay (Ownby and Heidhues, 1993), none of the mafias was ever formally registered as a legitimate association and precisely because of the lack of official recognition, their longevity, size, formalized structure, and elaborate cultural apparatus look exceptional in the panorama of organized crime (cf. Paoli, 2003, 2020; Reuter, 1983; Varese, 2020; Von Lampe, 2016). If one considers that OMCGs were until recently registered legal associations, the same traits look less remarkable, even if some of their cultural practices, such as initiation oaths, are more indicative of a secretive subculture, rather than, say, a contemporary recreational club.

From the current study, it becomes apparent that the answer to our core question—to what extent do Dutch OMCGs resemble mafia organization—cannot be a simple one. We have shown that there are similarities for some traits and hardly any similarities for others. We also note that Satudarah is closer to the mafias than the other OMCGs: it imposes comparable initiation rituals, including a blood oath, and is strongly socially embedded in the (local) Moluccan culture and communities. The general lesson that we draw from this comparative analysis is that even large-scale, formalized groups with an elaborate cultural apparatus do not necessarily possess considerable economic or political power, and hence that the latter cannot be automatically implied from the former characteristics of the groups.

We also hope to have shown the merits of comparative analyses, which, with few exceptions (e.g. Catino, 2019), are still rare in research on organized crime and other related criminal phenomena. In our opinion, such analyses are, first of all, essential to clarify our understanding of the different so-called organized crime actors and, on this basis, refine our theorizing on the factors that have prompted the emergence of the different types of actors. Comparative analyses are perhaps even more important to prevent misconceptions in society and among policymakers and to select appropriate policy measures for dealing with each set of organized actors and activities, making sure that such measures are commensurate to the threat posed and respectful of all parties’ legitimate rights.

Footnotes

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

ORCID iDs

Sjoukje van Deuren

Edward Kleemans

Letizia Paoli

Notes

References

Ayling

(2017) Combating organized crime Aussie-style: From law enforcement to prevention. In: Nelen

Siegel

(eds) Contemporary Organized Crime. Switzerland: Springer Nature, pp. 189–212.

Bjørgo

(2017) Preventing organised crime originating from outlaw motorcycle clubs. Trends in Organized Crime 22: 84–122.

Blokland

Soudijn

Van der Leest

(2017a) Outlaw bikers in the Netherlands: Clubs, social criminal organizations, or gangs? In: Bain

Lauchs

(eds) Understanding the Outlaw Motorcycle Gangs: International Perspectives. Carolina Academic Press, pp. 91–144.

Blokland

AAJ

(2019) Woorden maken werelden (en cijfers ook): Hoe hoog is nu het percentage veroordeelde outlawbikers? Tijdschrift voor Criminologie 61(3): 246–259.

Blokland

AAJ

David

(2016) Outlawbikers voor de rechter: Een analyse van rechterlijke uitspraken in de periode 1999-2015. Tijdschrift voor Criminologie 58(3): 42–64.

Blokland

AAJ

Soudijn

Teng

(2014) We zijn geen padvinders. Een verkennend onderzoek naar de criminele carrieres van leden van 1%-motorclubs. Tijdschrift voor Criminologie 3(3): 3–28.

Blokland

AAJ

Van der Leest

Soudijn

(2017b) Profielen van Nederlandse outlawbikers en Nederlandse outlawbikerclubs. Apeldoorn: Politie & Wetenschap, Universiteit Leiden.

Blokland

AAJ

Van Der Leest

Soudijn

(2020) Officially registered criminal careers of members of Dutch outlaw motorcycle gangs and their support clubs. Deviant Behavior 41(11): 1393–1412.

Blokland

AAJ

Van Hout

Van der Leest

, et al. (2019) Not your average biker; criminal careers of members of Dutch outlaw motorcycle gangs. Trends in Organized Crime 22(1): 10–33.

10.

Bouchard

Morselli

(2014) Opportunistic structures of organized crime. In: Paoli

(ed) The Oxford Handbook of Organized Crime. New York: Oxford University Press, pp. 288–302.

11.

Bovenkerk

Fijnaut

(1996) De georganiseerde criminaliteit in Nederland. Deventer: Gouda Quint.

12.

Campana

Varese

(2018) Organized crime in the United Kingdom: Illegal governance of markets and communities. The British Journal of Criminology 58(6): 1381–1400.

13.

Catino

(2019) Mafia Organizations: The Visible Hand of Criminal Enterprise. New York: Cambridge University Press.

14.

Chin

(2014) Chinese organized crime. In: Paoli

(ed) The Oxford Handbook of Organized Crime. Oxford: Oxford University Press, pp. 219–233.

15.

De Groot

(2015, December 15) Satudarah laat ander gezicht zien met kerstactie. Algemeen Dagblad. Available at: https://www.ad.nl/dordrecht/satudarah-laat-ander-gezicht-zien-met-kerstactie∼a9609960/.

16.

De Hoogh

(2014) Leider motorclub over massale uittocht van leden: ‘Dit maakt Satudarah alleen maar sterker’. De Nieuwe Revu 5(3020).

17.

Endedijk

Roox

(2022, October 4) Werkt Italiaanse aanpak ook bij onze ‘poldermaffia’? NRC. Available at: https://www.nrc.nl/nieuws/2022/10/05/werkt-italiaanse-aanpak-ook-bij-onze-poldermaffia-a4144256#:∼:text=Maffia%20Nederlandse%20bewindslieden%20kijken%20in,Nederland%20niet%20werken%2C%20zeggen%20deskundigen.

18.

Franck

(2016, May 2) Hells Angels in de bres voor kindjes met beperking. Nieuwsblad. Available at: https://www.nieuwsblad.be/cnt/dmf20160501_02268062.

19.

Gambetta

(1993) The Sicilian Mafia: The Business of Private Protection. Cambridge: Harvard University Press.

20.

Geurtjens

Nelen

Vanderhallen

(2018) From bikers to gangsters: On the development of and the public response to outlaw biker clubs in Germany, the Netherlands and Belgium. In: Kuldova

Sanchez-Jankowski

(eds) Outlaw Motorcycle Clubs and Street Gangs: Scheming Legality, Resisting Criminalization. Basingstoke: Palgrave Macmillan, pp. 93–121.

21.

Jahnsen

(2018) Scandinavian approaches to outlaw motorcycle gangs. Trends and Issues in Crime and Criminal Justice 543: 1–15.

22.

Kamp

(2014, January 23) Motorclub No Surrender: nieuwkomer in Zundert overschaduwt Satudarah. Omroep Brabant. Available at: https://www.omroepbrabant.nl/nieuws/1677359/motorclub-no-surrender-nieuwkomer-uit-zundert-overschaduwt-satudarah.

23.

Kaplan

Dubro

(1987) Yakuza: The Explosive Account of Japan’s Criminal Underworld. London: Futura.

24.

Kleemans

(2014) Organized crime research: Challenging assumptions and informing policy. In: Cockbain

Knutsson

(eds) Applied Police Research: Challenges and Opportunities. New York: Routledge, pp. 57–67.

25.

Klement

(2016) Outlaw biker affiliations and criminal involvement. European Journal of Criminology 13(4): 453–472.

26.

Koornstra

Roorda

Vols

, et al. (2019) Bestrijding van Outlaw Motorcycle Gangs: een rechtsvergelijkende studie naar de aanpak van onrechtmatige organisaties in rechtsstatelijk perspectief. Groningen: Rijksuniversiteit.

27.

Korps Landelijke Politiediensten (2010) Hells Angels en andere 1% MC's in Nederland. KLPD-Dienst Nationale Recherche en Politieregio Limburg-Zuid.

28.

Landelijke Eenheid (2014) Outlawbikers in Nederland. DLIO.

29.

Lauchs

Bain

Bell

(2015) Outlaw Motorcycle Gangs: A Theoretical Perspective. New York: Palgrave MacMillan.

30.

Layder

(1998) Sociological Practice: Linking Theory and Social Research. London: Sage Publications.

31.

Morgan

Dowling

Voce

(2020) Australian Outlaw motorcycle gang involvement in violent and organised crime. Trends and Issues in Crime and Criminal Justice 586: 1–16.

32.

Morgan

(1960) Triad Societies in Hong Kong. Hong Kong: Government Press.

33.

Murray

(1994) The Origins of the Tiandihui. The Chinese Triads in Legends and History. Standford, CA: Standford University Press.

34.

National Police Agency (2018) Police of Japan 2018. Tokyo: National Police Agency. Available at: https://www.npa.go.jp/english/Police_of_Japan/POJcontents.html.

35.

Ownby

Heidhues

(1993) Secret Societies Reconsidered: Perspectives on the Social History of Modern South China and Southeast Asia. Armonk, NY: M.E. Sharpe.

36.

Paoli

(2000) Fratelli di mafia: Cosa Nostra e ‘Ndrangheta. Bologna: Il Mulino.

37.

Paoli

(2003) Mafia Brotherhoods: Organized Crime, Italian Style. Oxford: Oxford University Press.

38.

Paoli

(2020) What makes mafia different? Crime and Justice 49: 141–222.

39.

Paoli

Peters

Reuter

(2024) Is the Sinaloa Cartel a Mafia? The British Journal of Criminology 64: 157–174.

40.

Reuter

(1983) Disorganized Crime: The Economics of the Visible Hand. Cambridge: MIT Press.

41.

Reuter

Paoli

(2020) How similar are modern criminal syndicates to traditional mafias? Crime and Justice 49: 223–287.

42.

RTV Drenthe (2016) No Surrender-voorman Henk Kuipers start landelijke politieke partij. Available at: https://www.rtvdrenthe.nl/nieuws/111935/no-surrender-voorman-henk-kuipers-start-landelijke-politieke-partij.

43.

Van Deuren

Blokland

AAJ

Kleemans

(2021) Differentiating between outlaw motorcycle gangs (OMCGs): Estimating the effect of membership of the most crime-prone OMCGs on crime using matching weights. Journal of Developmental and Life-Course Criminology 7(4): 649–675.

44.

Van Deuren

Blokland

AAJ

Kleemans

(2022b) Examining membership of Dutch outlaw motorcycle gangs and its association with individual criminal careers. Deviant Behavior 43(7): 880–895.

45.

Van Deuren

Hirsch Ballin

MFHH

Kleemans

, et al. (2022a) The Dutch judicial approach to various types of co-offending among members of Outlaw Motorcycle Gangs. Trends in Organized Crime. DOI: https://doi.org/10.1007/s12117-022-09461-2.

46.

Van Deuren

Kleemans

Blokland

AAJ

(2022c) Outlaw motorcycle gangs and their members’ crime: Examining the social organization of crime and its relationship to formal club hierarchy. European Journal of Criminology 19(6): 1461–1482.

47.

Van Deuren

Kleemans

Blokland

AAJ

(2024a) A conceptual framework of (illegal) governance behavior: A case study of Dutch outlaw motorcycle gangs. In: Blokland

AAJ

von Lampe Van Deuren

(eds) Outlaw Bikers as Organized Crime. New York: Routledge, pp. 133–148.

48.

Van Deuren

Roks

Van Ruitenburg

(2024b) Inside the Dutch Hells Angels: An empirical study into the club’s entry mechanisms. Trends in Organized Crime. DOI: https://doi.org/10.1007/s12117-023-09522-09.

49.

Van Kommer

(2020, April 11) Motorclub Hells Angels brengt chocolade en cadeau naar patiëntjes in Wilhelmina Kinderziekenhuis. Algemeen Dagblad. Available at: https://www.ad.nl/utrecht/motorclub-hells-angels-brengt-chocolade-en-cadeaus-naar-patientjes-in-wilhelmina-kinderziekenhuis∼affa8aead/.

50.

Van Ruitenburg

(2020) Raising Moral Barriers: An Empirical Study on the Dutch Approach to Outlaw Motorcycle Gangs. The Hague: Eleven International Publishing.

51.

Van Ruitenburg

Blokland

AAJ

(2022) The Dutch approach to outlaw motorcycle gangs. Trends and Issues in Crime and Criminal Justice, No. 655. Available at: https://www.aic.gov.au/sites/default/files/2022-09/ti655_dutch_approach_gangs.pdf.

52.

*Van Ruitenburg

van Deuren S Roks

(2024) How ‘outlaws’ react: a case study on the reactions to the Dutch approach to outlaw motorcycle gangs. European Journal on Criminal Policy and Research. DOI: https://doi.org/10.1007/s10610-023-09566-6.

53.

Varese

(2020) How mafias migrate: Transplantation, functional diversification, and separation. Crime and Justice. A Review of Research 49: 289–337.

54.

Visscher

(2014, April 8) Het broeit in wereld van omstreden motorclubs. Reformatorisch Dagblad. Available at: https://www.rd.nl/artikel/555710-het-broeit-in-wereld-van-omstreden-motorclubs.

55.

von Lampe

(2016) Organized Crime: Analyzing Illegal Activities, Criminal Structures, and Extra-Legal Governance. Thousand Oaks, CA: Sage Publications.

56.

von Lampe

Blokland

AAJ

(2020) Outlaw motorcycle clubs and organized crime. Crime and Justice 49: 521–578.

57.

Weber

(1978) Economy and Society: An Outline of Interpretive Sociology (eds Roth

Wittich

). Berkeley: University of California Press (Originally published 1922).

Outlaw motorcycle groups in the Netherlands: To what extent do they resemble mafia organizations?

Abstract

Keywords

Introduction

Theory

Internal traits

External traits

Current study

Data and methods

Results

Longevity

Large size

Formalized and complex structure

Elaborate cultural apparatus

Multifunctionality

Goal of political domination and long-standing ability to provide governance services

Legitimacy and power sharing

Discussion and conclusions

Footnotes

Declaration of Conflicting Interests

Funding

ORCID iDs

Notes

References