Biehler, Robert F.
Houghton Miffiln, [date of publication not identified]
Buku Teks
Muchinsky, Paul M., author
Wadsworth, 2000
Buku Teks
Bass, Bernard M., author
Allyn and Bacon, 1973
Buku Teks
McCormick, Ernest James, author
Prentice-Hall, 1985
Buku Teks
editor-in-chief Charles D. Spielberger
Hershey, 2004
Buku Teks