Nourse, Alan E.
Time Incorporated, 1964
Buku Referensi
Donatelle, Rebecca J.
Allyn and Bacon , 1997
Buku Teks
Macionis, John J.
Prentice-Hall, 2000
Buku Teks
Chandler, Daniel
Routledge, 2002
Buku Teks
Lauer, David A., 1955-2011
Thomson Learning, 1995
Buku Teks