Rose, Michael D.
St. Paul Minn, 1988
Buku Teks
Mcnulty, John K.
West Publishing Company, 1972
Buku Teks
Gaffney, Dennis J., author
McGraw-Hill, 1982
Buku Teks
Hudson, David M., author
St. Paul, Minn, 1994
Buku Teks
Andrews, William D., 1931-, author
Little, Brown, 1979
Buku Teks