Hill, Craig A., author
Sage Publications, 2008
Buku Teks
edited by Gregory J. Boyle, Donald H. Saklofske, Gerald Matthews
Academic Press, 2015
eBooks
Brekhus, Wayne.
MA Polity Press, 2015
Buku Teks
edited by John P. Robinson, Phillip R. Shaver, Lawrence S. Wrightsman
Academic Press, 1991
Buku Teks
Routledge, 2003
Buku Teks