Loomis, C. Grant
The Mediaeval Academy of America, 1948
Buku Teks
Metford, J.C.J., author
Thames and Hudson, 1983
Buku Referensi
Jones, Robert P. (Robert Patrick), author
Simon & Schuster Paperbacks, 2017
Buku Teks
editor, Maria Leach
Funk & Wagnalls Co., 1949
Buku Referensi
Brohier, R.L.
Lake House Investments, 1971
Buku Teks