Below is a selection taken from a list of resources provided courtesy of Becca Bailey, who completed a philosophy and geometry project during the fall 2002 term. Thanks Becca!

1. Chihara, Charles S. Ontology and the Vicious-Circle Principle. Cornell Univ. Press; London; 1973

2. Gensler, Harry J. Godel's Theorem Simplified. University Press of America; Boston; 1984

3. Hofstadter, Douglas R. Godel, Escher, Bach: an Eternal Golden Braid. Basic Books; New York; 1979

4. http://www.cut-the-knot.com/triangle/pythpar/NonEuclid.shtml

5. http://www.geom.umn.edu/docs/forum/sos