 The History of Counting by Denise SchmandtBesserat, Michael Hays, August, 1999
 Counting on Frank by Rod Clement, December, 1991
 The Key of It All: An Encyclopedic Guide to the Sacred Languages & Magickal Systems of the World: Book One: The Eastern Mysteries (Llewellyn's Sou) by David Allen Hulse, December, 1993
 Number Words and Number Symbols: A Cultural History of Numbers by Karl Menninger, Paul Broneer, May, 1992
 Big Numbers by Edward Packard, March, 2000
 The Nashville Number System by Chas Williams, Williams Chas, 11 April, 2001
 From One to Zero: A Universal History of Numbers by Georges Ifrah, February, 1987
 Euler Systems by Karl Rubin, 01 May, 2000
 Mathematical Thinking at Grade 5: Introduction & Landmarks in the Number System (Investigations in Number, Data, and Space Series) by Marlene Kliman, Cornelia Tierney, et all May, 1997
 Discrete Dynamical Systems: Theory and Applications by James T. Sandefur, November, 1990
