Howard, Marshall C.
Englewood Clifts, 1983
Buku Teks
Fugate, Wilbur L., author
Little, Brown, 1982
Buku Teks
The Foundation Press, Inc., 1975
Buku Teks
Garvey, George E., author
Greenwood Press, 1990
Buku Teks
Hovenkamp, Herbert, author
West Publishing, 1993
Buku Teks