King, L. Thomas
New York, N.Y. : John Wiley & sons 1981,
Buku Teks
Allen, Carol Vestall, author
Appleton & Lange, 1997
Buku Teks
Rasiel, Ethan M., author
McGraw-Hill, 2001
Buku Teks
Snover, Stephen L., author
Prentice-Hall, 1982
Buku Teks
Robertson, S. Ian, author
Psychology Press, 2001
Buku Teks