Donald Routledge Hill, "Mechanical Engineering in the Medieval Near East", Scientific American, May 1991, p. 64-69. (cf. Donald Routledge Hill, Mechanical EngineeringArchiválva2007. december 25-i dátummal a Wayback Machine-ben)
Donald Routledge Hill, "Mechanical Engineering in the Medieval Near East", Scientific American, May 1991, p. 64-69. (cf. Donald Routledge Hill, Mechanical EngineeringArchiválva2007. december 25-i dátummal a Wayback Machine-ben)