Skousen, K. Fred, author
South-Western, 1993
Buku Teks
Jandt, Fred E.
Sage pub., 2016
Buku Teks
Ratner, David L., author
West Publishing, 1992
Buku Teks
Ratner, David L., author
West Publishing, 1996
Buku Teks
Bloomenthal, Harold S., author
Little, Brown, 1977
Buku Teks