Hacker 1968, p. 43. Hacker, Barton C. (January 1968), "Greek Catapults and Catapult Technology: Science, Technology, and War in the Ancient World", Technology and Culture, 9 (1): 34–50, doi:10.2307/3102042, JSTOR3102042
Hacker 1968, p. 43. Hacker, Barton C. (January 1968), "Greek Catapults and Catapult Technology: Science, Technology, and War in the Ancient World", Technology and Culture, 9 (1): 34–50, doi:10.2307/3102042, JSTOR3102042