The Dushkin Publishing Group, Inc., 1992
Buku Teks
Back, Kurt W.
John Wiley & Sons, 1977
Buku Teks
Mayer, Robert R.
Prentince-Hall, 1980
Buku Teks
London, Kurt, editor
D.van Nostrand Company,Inc., 1950
Buku Teks
Green, Paul E.
Prentice-Hall, 1970
Buku Teks