^Lyons, Malcolm Cameron and David Edward Pritchett Jackson, Saladin: The Politics of the Holy War, Cambridge University Press, 1982, p. 2;"According to this, two Kurdish brothers from Dvin near Tiflis, Ayyub and Shirkuh, moved to Iraq..."
^George F. Nafziger; Mark W. Walton, Islam at War: A History, Praeger, 2003, p. 42.