Wilson, Woodrow
Columbia University, [date of publication not identified]
Buku Teks
Cooley, Thomas M.
Little, Brown and Company, 1898
Buku Teks
Swisher, Carl Brent, author
University of Chicago Press, 1946
Buku Teks
introduction by Edward G. Smith
Barnes & Noble, 1966
Buku Teks
Dumbauld, Edward, author
University of Oklahoma Press, 1946
Buku Teks