Retrieved on 2008-06-22 ↑ Dunham 1994, p. 227 ↑ "Archimedes: His Works", Britannica Online, Encyclopædia Britannica, retrieved 23 June 2008 ↑ (Dunham 1994, p. 226) ↑ Károly Simonyi (2012). A Cultural History of Physics. CRC Press. p. 88.