Edward Edgar, 1994
Buku Teks
Bobrow, Davis B.
Free Press, 1979
Buku Teks
edited by Charles F. Herman, Charles W. Kegley, James N. Rosenau
Harper Collins Academic, 1987
Buku Teks
Millar, T.B., author
Georgian House, 1972
Buku Teks
Roseman, James N
The Free Press, 1971
Buku Teks