Nagle, John D.
Sage Publications, 1999
Buku Teks
Tocqueville, Alexis de, author
The Bantam Classic, 2000
Buku Teks
Ross, Alf, author
Harvard University Press, 1952
Buku Teks
edited by Richard M. Ketchum
Dutton, 1955
Buku Teks
Becker, Carl L. (Carl Lotus), 1873-1945, author
Yale University Press, 1959
Buku Teks