Voir page 13 in The mathematics of Egypt, Mesopotamia, China, India, and Islam: a sourcebook, Victor J. Katz & Annette Imhausen, Princeton University Press, 2007
Voir page 118 in Encyclopedic dictionary of mathematics - EDM 2, Kiyosi Itô, MIT Press, 2000
Voir pages 40-41 in The Technology of Mesopotamia, Graham Faiella, Rosen Publishing, 2006
Voir pages 111-114 in 'The first writing: script invention as history and process, sous la direction de Stephen D. Houston, Cambridge University Press, 2004
Voir aussi page 341 in Abstraction and representation: essays on the cultural evolution of thinking, Peter Damerow, Luwer Academic Publishers, 1996