edited, Bridget Somekh, Cathy Lewin
Sage Publications , 2005
Buku Teks
Simon, Julian L.
Random House , 1978
Buku Teks
Martin, Brian, author
Freedom Press, 1993
Buku Teks
Ponsioen, J.A.
Mouton, 1969
Buku Teks
edited by Gerald Zaltman, Philip Kotler, Ira Kaufman
Holt, Rinehart and Winston, 1972
Buku Teks