Ward, John, author
Routledge , 1997
Buku Teks
Divine, Robert A., author
Alfred A. Knopf, 1985
Buku Teks
Palmer, R.R. (Robert Roswell), 1909-2002, author
McGraw-Hill, 1992
Buku Teks
Robinson, Francis, author
Facts on File, 1982
Buku Referensi
Toynbee, Arnold J., author
Oxford University Press, 1957
Buku Teks