PeckBaey Lian (1978) President, Singapore Anti-Narcotics Association. Personal communication.
2.
RittenhouseJ. N., (ed.) (1977) The epidemiology of heroin and other narcotics. NIDA Research Monograph 16U.S. Government Printing Office, Washington, D.C.
3.
SenateU.S. (1975) Marihuana-Hashish Epidemic and its Influence on United States Security.U.S. Government Printing Office, Washington, D.C.
4.
WardlawG. (1978). Drug Use and Crime.Australian Institute of Criminology, Canberra.