Beus, J. G. De
Harper & Brothers, 1953
Buku Teks
Ward, Barbara
Norton & Comp , 1957
Buku Teks
Toynbee, Arnold J.
Oxford University Press, 1957
Buku Teks
Carpenter, Allan
Facts On File, 1990
Buku Referensi
editors Charles Phillips, Alan Axelrod
Simon & Schuster Macmillan, 1996
Buku Referensi