Lieberman, Jethro Koller.
Harcourt Brace Jovanovich, 1989
Buku Teks
Willborn, Steven L.
The Michie Company, 1993
Buku Teks
Armey, Dick
Fawcett Columbine, 1996
Buku Teks
Sloan, Irving J.
Ocean Publications, 1988
Buku Teks
Moran, Robert D., author
Moran Associates, 1992
Buku Teks