TarnaiT., Cutting patterns for inflatables: Soccer ball designs, Int. IASS Conference, Bucharest, 6–10 September 2005, p.765–772.
2.
SchaperH.SchaperF., Inflatable ball for ball games, in particular football, International Patent Application PCT/NL93/00147, 9 July 1992.
3.
ObermannG., Sport und Spielball, German Patent Application 6 89 08 027.0, 30 June 1989.
4.
HuybersP., The chiral polyhedra, IASS Journal, vol. 40, No. 2, August 1999, p. 133–143 (Awarded with the Tsuboi Price 2000 of IASS, Int. Association of Shell and Spatial Structures).
5.
HuybersP., Ball composed of two types of equilateral parts, Int. Patent Application PCT/NL98/00459, 12 August 1998.
6.
HuybersP., Ball with improved properties, PCT-request PCT/NL2003/00557, dated 20 August 2002.
7.
HuybersP., In search of the roundest soccer ball, Int. Conference on Adaptability in Design and Construction, Eindhoven, 3–5 July, 2006, p. 6.115–6.121.
