Axelrod, C. Warren, author
John Wiley & Sons, 1982
Buku Teks
Axelrod, Warman, author
Prentice-Hall, 1982
Buku Teks
Ridge, Warren J., author
Illinois Dow Jones-Irwin , 1973
Buku Teks
Halford, D.R.C., author
Pan Books, 1971
Buku Teks
Schaeffer, Howard
Prentice Hall Inc., 1981
Buku Teks