References
[Suppes et al., 1989]
Suppes, Patrick; Krantz, David H.; Luce, R. Duncan, and Tversky, Amos. Foundations of measurement: geometrical, thereshold, and probalistic representations. San Diego; London: Academic Press; 1989. ISBN: 0-12-425402-0.
Cyberspace geography visualization - 15 October 1995
Luc Girardin, The Graduate Institute of International Studies