References
[Krantz et al., 1971]
Krantz, David H.; Luce, R. Duncan; Suppes, Patrick, and Tversky, Amos. Foundations of measurement: additive and polynomial representations. San Diego; London: Academic Press; 1971. University of Fribourg; ISBN: 0-12-425401-2.
Cyberspace geography visualization - 15 October 1995
Luc Girardin, The Graduate Institute of International Studies