Craven, Paul R.
Dickenson Publishing, 1968
Buku Teks SO
Brandes, Joseph
University of Pittsburgh Press, 1962
Buku Teks
Peeters, Benoît, 1956-
Polity Press, 2013
Buku Teks
Berg, A.Scott
Riverhead Books, 1989
Buku Teks
Josephson, Matthew
McGraw-Hill, 1959
Buku Teks