Brandon/Systems Press, 1970
Buku Teks SO
Solomon, Irving I.
New American Library , 1968
Buku Teks
Eliason, Alan L.
Macmillan, 1991
Buku Teks SO
Fuori, William M.
Prentice-Hall, 1981
Buku Teks SO
Kroenke, David M., 1946-
Mitchell Publishing, 1987
Buku Teks SO