Nickels, William G.
Marketing communications and promotion
Grid, INC , 1976
 Buku Teks
Kotler, Philip
Marketing moves : a new approach to profits, growth, and renewal
Harvard Business School Press, 2002
 Buku Teks
Christensen, Mary, 1951-
Be a recruiting superstar: the fast track to network marketing millions
American Management Association, 2008
 eBooks
Roberts, Mary Lou
Direct marketing management
Prentice-Hall, 1989
 Buku Teks
The Direct marketing handbook
Edward L. Nash, editor in chief
McGraw-Hill , 1992
 Buku Referensi