(en) Graham Loud, The Age of Robert Guiscard
Southern Italy and the Northern Conquest, Taylor & Francis, , 342 p. (ISBN978-1-317-90022-1, lire en ligne)
(en) Paul Brown, Mercenaries to Conquerors
Norman Warfare in the Eleventh and Twelfth-Century Mediterranean, Pen & Sword Books, , 272 p. (ISBN978-1-473-88010-8, lire en ligne)
(en) Christopher Gravett, Norman Stone Castles (2)
Europe 950–1204, Bloomsbury Publishing, (ISBN978-1-782-00145-4, lire en ligne)
(en) Joshua C. Birk, Norman Kings of Sicily and the Rise of the Anti-Islamic Critique
Baptized Sultans, Springer International Publishing, , 371 p. (ISBN978-3-319-47042-9, lire en ligne), p. 56
(en) Gordon S. Brown, The Norman Conquest of Southern Italy and Sicily, McFarland, Incorporated, Publishers, , 222 p. (ISBN978-0-786-45127-2, lire en ligne), p. 176