Conklin, William E., author
Ashgate, 1998
Buku Teks
Goodrich, Peter
Macmillan, 1987
Buku Teks
Day, Ronald E., author
Southern Illinois University Press, 2001
Buku Teks
Lacour, Claudia Brodsky
Duke University Press, 1996
Buku Teks
Redden, Kenneth R., author
The Michie Company, 1980
Buku Referensi