Southern, R.W. (Richard William), 1912-2001
The making of the Middle Ages
Cresset Librar, 1967
 Buku Teks
Hoyt, Robert S.
Europe in the middle ages
Harcourt, Brace & World, 1966
 Buku Teks
Perroy, Edouard, 1901-1974
Le Moyen age l'expansion de l'Orient et la naissance de la civilisation occidentale
Presses Universitaires de France, 1961
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Fremantle, Anne
Age of faith / by Anne Fremantle and the editors of Time-Life Books.
Time Life International, 1965
 Buku Teks
The Middle Ages : a concise encyclopaedia
general editor, H.R. Loyn
Thames and Hudson, 1991
 Buku Referensi