Howard, John R., author
J.B. Lippincott, 1974
Buku Teks
Morales, Armando, author
Allyn and Bacon, 1977
Buku Teks
Kadushin, Alfred, author
Columbia University Press, 2014
Buku Teks
Cohen, Nathan Edward, author
Holt, Rinehart and Winston, 1958
Buku Teks
Ringer, Robert J.
Fawcett Crest, 1980
Buku Teks