Seery, John Evan
Westview Press , 1990
Buku Teks
Edward, David V.
Prentice-Hall, 1982
Buku Teks
edited by Robert E. Ward & Dankward A. Rustews
Princeton University Press, 1968
Buku Teks
Lane, Robert E.
The Free Press, 1972
Buku Teks
Good, Yohn M
Heath, 1970
Buku Teks