Newman, Joseph W.
Harper & Brothers, 1971
Buku Teks
Drummond, Helga, author
John Wiley & Sons, 2001
Buku Teks
Albert, Henry H., author
John Wiley & Sons, 1961
Buku Teks
Churchman, Charles West, 1913-, author
Prentice-Hall, 1961
Buku Teks
Radford, K.J., author
Prushin-Hall, 1974
Buku Teks