Hacker, Barton C (1968), „Greek Catapults and Catapult Technology: Science, Technology, and War in Ancient World”, Technology and Culture, 9 (1): 34—50, JSTOR3102042, doi:10.2307/3102042.
Hacker, Barton C (1968), „Greek Catapults and Catapult Technology: Science, Technology, and War in Ancient World”, Technology and Culture, 9 (1): 34—50, JSTOR3102042, doi:10.2307/3102042.
The Trebuchet, Citation:"The trebuchet, invented in China between the fifth and third centuries B.C.E., reached the Mediterranean by the sixth century C.E. "