Venkatesan, M., author
Free Press, 1971
Buku Teks
ESOMAR, 1972
Buku Teks
Barksdale, Hiram C., author
Holt, Rinehart and Winston, 1963
Buku Teks
Aaker, David A., author
John Wiley & Sons, 1995
Buku Teks
Churchill, Gilbert A., author
Thomson, 2005
Buku Teks