TheSandReckoner 511 R U, by Ilan Vardi (页面存档备份,存于互联网档案馆), accessed 28-II-2007. Newman, James R. — The World of Mathematics (2000), p. 420 TheSand-Reckoner
Spirals; On the Equilibrium of Planes; On the Quadrature of the Parabola; TheSandReckoner. World Digital Library. 1450–1460 [2013-07-13]. (原始内容存档于2021-03-21)