Babylonian clay tablet, disovered in 1900 thought to have been written about 1800 BC. Currently a number 322 in the G.A. Plimpton Collection at Columbia University. Partly broken is 13 cm wide, 9 cm tall, and 2 cm thick. This inscription contains nowaday named the Pythagorean triples.
- Laurence Kirby, Plimpton 322: The Ancient Roots of Modern Mathematics (Half-hour video documentary), Baruch College, City University of New York 2011.
- Bill Casselman, The Babylonian tablet Plimpton 322, 2003 - http://www.math.ubc.ca/~cass/courses/m446-03/pl322/pl322.html
- Evert M. Bruins, "On Plimpton 322, Pythagorean numbers in Babylonian mathematics", Koninklijke , pp. 117–121.
- David E. Joyce: Laurence Kirby, Plimpton 322: 1995 - https://mathcs.clarku.edu/~djoyce/mathhist/plimpnote.html