Lamont, Douglas, author
Blackwell Publishers, 1996
Buku Referensi
Kotler, Philip, author
[publisher not identified], [date of publication not identified]
Buku Teks
Kotler, Philip, author
Prentice-Hall, 2000
Buku Teks
Wilson, Mike, author
Gower Publishing, 1985
Buku Teks
Boyd, Harper W., Jr., author
Harcourt Brace Jovanovich, 1972
Buku Teks