Hughes, Gerard J.
Routledge, 1995
Buku Teks
Griffith, John R.
Lexington Books, 1972
Buku Teks
Correa, Hector
International Textbook , 1969
Buku Teks
Palys, T.S. (Theodore Stephen)
Nelson Education, 2014
Buku Teks SO
Ragin, Charles C.
University of California Press, 1987
Buku Teks SO