Adams, Katherine H.
Mayfield Publishing Company, 2000
Buku Teks SO
Marcus, Leonard J.
Jossey-Bass, 1995
Buku Teks
Rockefeller College Press, 1988
Buku Teks
edited by Romulo Pinheiro, Lars Geschwind, Francisco O. Ramirez, Karsten Vrangbaek
Emerald, 2016
eBooks
Fasel, Diane K.
Pathways, 2000
Buku Teks