Mary Kupiec Cayton, Elliott J. Gorn, Peter W. Williams, editors
Charles Scribner's Sons, 1993
Buku Referensi
Clark, Victor S.
Peter Smith, 1949
Buku Teks SO
Murdoch, James
Routledge , 1926
Buku Referensi
Baron, Salo Wittmayer
Columbia University Press, 1957
Buku Teks SO
Toynbee, Arnold J.
Oxford University Press, 1956
Buku Teks SO