Hoover, Kenneth R., 1940-
Thomson, 2008
Buku Teks
Hoover, Kenneth R., 1940-
Thomson, 2004
Buku Teks
Donovan, Todd
Wadsworth and Cengage Learning, 2014
Buku Teks
Shiraev, Eric B.
Pearson/Allyn and Bacon, 2004
Buku Teks
Parrillo, Vincent N.
John Wiley & Sons, 1985
Buku Teks