Hefferon, Jim
Saint Michaels College, 2000
Buku Teks
Anton, Howard, author
John Wiley & Sons, 1991
Buku Teks
Olver, Peter J., author
Prentice-Hall, 2006
Buku Teks
Kolman, Bernard, 1932-, author
Prentice-Hall, 2008
Buku Teks
Shields, Paul C., author
Worth Publishers, 1980
Buku Teks