Reny de Leeuw, Gary D. Klasser, editors
Quintessence Publishing Co, Inc, 2013
Buku Teks
Klineberg, Iven, author
Boston Wright , 1991
Buku Teks
John Wiley & Sons, 2000
Buku Teks
Higgs, Zana Rae, author
FA. Davis, 1985
Buku Teks
Levy, Howard B.
Raven Press , 1984
Buku Teks