Rogers, Peter
FA. Davis, 1977
Buku Teks
edited by Marcello Truzzi
Prentice-Hall, 1968
Buku Teks
Felson, Marcus
Pine force Press, 1998
Buku Teks
Ross, Martin J., author
A Fawcett Crest Book, 1975
Buku Teks
edited by Hugh Mackay
The Open University, 1997
Buku Teks