Bien, Thomas, author
Wisdom Publications, 2006
Buku Teks
McLeod, John, author
McGraw-hill Open University press, 2012
Buku Teks
by Nancy McCormark and Catherine Cotter
Chando, 2013
eBooks
Marvin R. Goldfried, editor
American Psychological Association, 2001
Buku Teks
Gehart, Diane R., author
Springer, 2012
eBooks