Liebert, Robert M., 1942-
Prentice-Hall, 1995
Buku Teks SO
RAy, William J.
Wadsworth, 1985
Buku Teks SO
Kalish, Harry I.
McGraw-Hill, 1981
Buku Teks SO
McMahon, Frank B.
The Dorsey Press, 1986
Buku Teks SO
edited by Sigmund Koch, David E. Leary
APA, 2006
Buku Teks SO