Southern, R.W. (Richard William), 1912-2001, author
Cresset Librar, 1967
Buku Teks
edited by C.G. Crump and E.F. Jacob
Clarendon Press, 1951
Buku Teks
Hoyt, Robert S., author
Harcourt, Brace & World, 1966
Buku Teks
general editor, H.R. Loyn
Thames and Hudson, 1991
Buku Referensi
Painter, Sidney
Alfred A. Knopf, 1961
Buku Teks