Sheafor, Bradford W., author
Allyn and Bacon, c2000
Buku Teks
editor, Bruce A. Thyer
Sage Publications, 2001
Buku Referensi
Routledge, 2015
Buku Teks
edited by Christine Knott
Learning Matters, 2010
Buku Teks
Cohen, Nathan Edward, author
Holt, Rinehart and Winston, 1958
Buku Teks