Kuther, Tara L., editor
Wadsworth and Cengage Learning, 2012
Buku Teks
Kuther, Tara L., editor
Wardworth, 2012
Buku Referensi
John Wiley & Sons, 2003
Buku Teks SO
Heiserman, David L.
Prentice-Hall, 1977
Buku Referensi
by Gordon W. Allport ... [et al.]; edited by Gardner Lindzey
Addison-Wesley, 1956
Buku Teks