Runciman, Lex, author
Allyn and Bacon, 1999
Buku Teks
Jordan, John E.
Harper & Row, Publishers, 1965
Buku Teks
Winterowd, W. Ross
Holt, Rinehart and Winston, 1968
Buku Teks
Winterowd, W. Ross
Harcourt Brace Jovanovich, 1981
Buku Teks
Connolly, Francis
Harcourt, Brace & World, 1969
Buku Teks