Fox, David J.
Appletton century crofts , 1982
Buku Teks
Ackoff, Russell Lincoln, 1919-, author
John Wiley & Sons, 1968
Buku Teks
Young, Felina C., author
IPWI, 1999
Buku Teks
Jacobstein, J. Myron
Foundation press, 1979
Buku Teks
edited by George Zinkhan
American Marketing Association, 2000
Buku Teks