John Baer, James C. Kaufman, Roy F. Baumeister, editor
Oxford University Press, 2008
Buku Teks SO
Hasselbeck, Elisabeth, author
Center Street, 2009
Buku Teks
Irving, John, author
New York: Ballantine Books, 1968,
Buku Teks
Cohn, P.M., author
Academic Press, 1985
Buku Teks
Holt, Robert T., author
University of Minnesota Press, 1958
Buku Teks