Peterson, Jim
Emerald, 2017
eBooks
Garland Publishing, Inc, 1996
Buku Teks
edited by Gregory A. Kimble, Michael Wertheimer, Charlotte White
American Psychological Association, 1991
Buku Teks SO
Cramer, John
Allen & Unwin, 1989
Buku Teks
Warren, Carl S.
South-Western College, 1999
Buku Teks