Rosati, Jerel A., 1953-
Wadsworth, 2007
Buku Teks
edited by Robert W. Tucker, Charles B. Keely, and Linda Wrigley
Westview Press, 1990
Buku Teks
Pratt, Julius W.
Prentice-Hall, 1965
Buku Teks
Brookings institution, 1949
Buku Teks
Brokings Institution, 1950
Buku Teks