Isaacson, Robert L., author
Harper & Row, 1965
Buku Teks
Carlson, Neil R., author
Allyn and Bacon, 1993
Buku Teks
Carlson, Neil R., author
Allyn and Bacon , 1997
Buku Teks
edited by Sigmund Koch, David E. Leary
APA, 2006
Buku Teks
McMahon, Frank B., author
The Dorsey Press, 1986
Buku Teks