Henry Melvill Gwatkin(英语:Henry Melvill Gwatkin); JamesPounderWhitney(英语:JamesPounderWhitney). The Cambridge Medieval History: Volume III. 剑桥大学出版社(Cambridge
Henry Melvill Gwatkin(英语:Henry Melvill Gwatkin); JamesPounderWhitney(英语:JamesPounderWhitney). The Cambridge Medieval History: Volume III. 剑桥大学出版社(Cambridge
5000 Years of Combat,第93頁 John Bagnell Bury、Henry Melvill Gwatkin、JamesPounderWhitney、Joseph Robson Tanner、Charles William Previté-Orton、Zachary Nugent