Schusky, Ernest l.
Holt Rinehart and Winston, 1975
Buku Teks
Routledge, 1996
Buku Teks
Ember, Carol R., author
Prentice-Hall, 1988
Buku Teks
Kottak, Conrad Phillip, author
McGraw-Hill, 2012
Buku Teks
Marcus, George E.
The University of Chicago Press, 1986
Buku Teks