Winick, Charles, author
Littlefield, Adams & Co., 1961
Buku Referensi
Corsini, Raymond J., author
Brunner-Routledge, 2002
Buku Referensi
David D. Kemp
Routledge, 1998
Buku Referensi
Singleton, Paul, author
John Wiley & Sons, 1980
Buku Referensi
Hinsie, Leland E., author
Oxford University Press, 1960
Buku Referensi