Wilson, Bright E., Jr.
Dover Publications, 1990
Buku Teks
Churchman, Charles West, 1913-
Wiley, 1957
Buku Teks
Churchman, Charles West, 1913-
John Wiley & Sons, 1957
Buku Teks
Churchman, Charles West, 1913-
John Wiley & Sons, 1961
Buku Teks
Wiersma, William
Pearson/Allyn and Bacon, 2005
Buku Teks