The legacy of the middle ages
edited by C.G. Crump and E.F. Jacob
Clarendon Press, 1951
 Buku Teks SO
Hoyt, Robert S.
Europe in the middle ages
Harcourt, Brace & World, 1966
 Buku Teks SO
The Middle Ages : a concise encyclopaedia
general editor, H.R. Loyn
Thames and Hudson, 1991
 Buku Referensi
Painter, Sidney
A history of the middle ages 284-1500 / Sidney Painter
Alfred A. Knopf, 1961
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The Middle ages : an encyclopedia for students volume 1-4
editor, William Chester Jordan
Charles Scribner's Sons, 1996
 Buku Referensi