Palmer, James O., author
Wiley, 1983
Buku Teks
Simeonsson, Rune J., author
Allyn and Bacon, 1986
Buku Teks
Friedrich, William N., author
Sage Publications, 2001
Buku Teks
American Psychological Association, 1997
Majalah, Jurnal, Buletin
edited by Laura A. Cushman and Marcia J. Scherer
American Psychological Association, 1995
Buku Teks