Gibbon 1776–1789. Gibbon, Edward (1776–1789), «LI The Conquest Of Persia, Syria, Egypt, Africa, And Spain, By The Arabs Or Saracens. — Empire Of The Caliphs, Or Successors Of Mahomet. — State Of The Christians, &c., Under Their Government.», The History of the Decline and Fall of the Roman Empire (em inglês), consultado em 22 de junho de 2013