The MacTutor History
of Mathematics archive http://turnbull.dcs.st-and.ac.uk/~history/
Eric W. Weisstein
http://mathworld.wolfram.com/PlatonicSolid.html © 1999-2002 Wolfram Research,
Inc.
Pi
history http://www-groups.dcs.st-and.ac.uk/~history/HistTopics/Pi_through_the_ages.html
Polyhedra, Peter R. Cromwel, Cambridge university presh, 1997.
The geometry junkyard,
Seventeen Proofs of Euler's Formula: V-E+F=2 http://www.ics.uci.edu/~eppstein/junkyard/euler/
Coxeter, H. S. M. Regular Polytopes, 3rd ed. New York: Dover, 1973.
The story
of the 120-cell by John Stillwell http://www.ams.org/notices/200101/fea-stillwell.pdf
Regular
Polytopes (Platonic solids) in 4D http://www.astronomy.swin.edu.au/~pbourke/polyhedra/platonic4d
Platonic Solids in
All Dimensions John Baez May 14, 1998, http://math.ucr.edu/home/baez/platonic.html
George Olshevsky's Four
Dimensional Figures Page http://members.aol.com/Polycell/uniform.html
Home page of James M. Gibbs
creator of a 4D polytope viewer in Java
2003, Symen H. Hovinga