Brookings institution, 1949
Buku Teks
Brokings Institution, 1950
Buku Teks
Mangone, Gerard J.
Syracuse University Press, 1962
Buku Teks
Pratt, Julius W., author
Prentice-Hall, 1965
Buku Teks
edited by Robert W. Tucker, Charles B. Keely, and Linda Wrigley
Westview Press, 1990
Buku Teks