References
[Kohonen et al., 1995]
Kohonen, Teuvo; Hynninen, Jussi; Kangas, Jari, and Laaksonen, Jorma. The self-organizing map program package. Version 3.1. 1995 April 7. <URL:ftp://cochlea.hut.fi/pub/som_pak/som_pak-3.1.tar.Z>.
Cyberspace geography visualization - 15 October 1995
Luc Girardin, The Graduate Institute of International Studies