Carr, Stuart C., author
John Wiley and Sons Australasia , 2003
Buku Teks
DeLamater, John D., author
Colorado Westview Press, 2014
Buku Teks
Pines, Ayala, author
McGraw-Hill, 1993
Buku Teks
Baron, Robert A., author
Heights Allyn and Bacon , 1991
Buku Teks
Brekhus, Wayne.
MA Polity Press, 2015
Buku Teks