Howells, William D., author
Doubleday, 1967
Buku Teks
Brace, C. Loring, author
Prentice-Hall, 1979
Buku Teks
edited by Eric Delson, Ian Tattersall, John A. Van Couvering and Alison S. Brokks
Garland Publishing, 2000
Buku Referensi
Wendt, Herbert, author
Houghton-Mifflin, 1956
Buku Teks
McKee, Jeffrey K., author
Pearson/Prentice Hall, 2005
Buku Teks