Marotz, Lynn R., author
Wadsworth and Cengage Learning, 2012
Buku Teks
Pedersen, Paul, author
American Association for Counseling and Development, 1988
Buku Teks
edited by Joseph D. Noshpitz
John Wiley & Sons, 1997
Buku Referensi
editor-in-chief Richard M. Lenrner
New Jersey Wiley, 2015
Buku Referensi
editor-in-chief Richard M. Lenner
New Jersey Wiley, 2015
Buku Referensi