1Arndt, Jörg and Christoph Haenel. Pi Unleashed. Trans. Catriona and David Lischka. New York, NY: Springer-Verlag Berlin Heidelberg, 2001.
2“Baffling Crop Circles Equal Pi.” Metro. June 18, 2008. Accessed: June 15, 2009.
3Beckmann, Petr. A History of Pi. New York, NY: Golem Press, 1971.
4Blatner, David. The Joy of Pi. New York, NY: Walker Publishing Company, 1997.
5Brown, James Robert. Philosophy of Mathematics: A Contemporary Introduction to the World of Proofs and Pictures. 2nd ed. New York, NY: Routledge, 2008.
6Maor, Eli. To Infinity and Beyond: A Cultural History of the Infinite. Princeton, NJ: Princeton University Press, 1987.
7“Pi by Givenchy.” Basenotes. Accessed: June 14, 2009.
8Pickover, Clifford A. Keys to Infinity. Denver, CO: John Wiley & Sons, Inc.
9“Pi: Faith in Chaos.” IMDB. Accessed: June 15, 2009.
10The Pi-Search Page. Angio. Updated April 17, 2006. Accessed: June 15, 2009.
11Tubbs, Robert. What Is a Number?: Mathematical Concepts and Their Origins. Baltimore, MD: The John Hopkins University Press, 2009.
12Zebrowski, Ernest, Jr. A History of the Circle: Mathematical Reasoning and the Physical Universe. New Brunswick, NJ: Rutgers University Press, 1999.