Wilber, Donald N.
Princeton University Press, 1958
Buku Teks
Bersoff, Donald N.
American Psychological Association , 1999
Buku Teks
Macdonald, Donald Stone
Westview Press, 1988
Buku Teks
edited by Robert D. Putnam
Oxford University Press, 2002
Buku Teks
Fried, Morton H., author
Random House, 1967
Buku Teks