Gilpin, Robert
Princeton University Press, 1987
Buku Teks
edited by John Ravenhil
Oxford University Press, 2014
Buku Teks
Balaam, David N., 1950-
Pearson/Prentice Hall, 2005
Buku Teks
Balaam, David N., 1950-
Prentice-Hall, 1996
Buku Teks
edited by W. Ladd Hollist
Westview Press, 1985
Buku Teks