Dawson, Paul
Routledge, 2005
Buku Teks
edited by Peter Burke
Pennsylvania State University Press, 1995
Buku Teks
Hilliard, Robert L., 1925-
Cengage Learning, 2015
Buku Teks
Encyclopaedia Britannica Inc., 2003
Buku Referensi
Encyclopedia Britannica, 1983
Buku Referensi