[b] H. E. Napier, op. cit.
[c] J. C. L. Sismondi, op. cit.
[d] G. B. Testa, op. cit.
Chapter III. The Normans in Sicily
[b] Gofredus Malaterra, Rerum Roberti Guiscardi et Rogerii fratris ejus.
[c] E. A. Freeman, articles on “Normans” and “Sicily” in the Encyclopædia Britannica.
[d] Henry Hallam, The State of Europe during the Middle Ages.
[e] Flodoard, Annales.
[f] Adhémar de Chabannes, Chronicon.
[g] G. B. Depping, Histoire des Expéditions maritimes des Normands.