Keeton, William T.
W.W. Norton, 1967
Buku Teks
Freeman, Scott
Prentice-Hall, 2002
Buku Teks
edited by Irving William Knobloch
Appleton-Century-Crofts, 1967
Buku Teks
Keeton, William T.
Penguin Books, 1976
Buku Teks
Herren, Ray V.
Delmar Cengage Learning, 2012
Buku Teks