Johnson, Robert, author
PWS-Kent, 1984
Buku Teks
Bowley, Arthur, author
Staples Press, 1948
Buku Teks
Erickson, Roy V., author
Allyn and Bacon, 1985
Buku Teks
Fleming, Michael C., author
Rouledge, 1994
Buku Teks
Berenson, Mark L., author
Prentice-Hall, 1988
Buku Teks