



Vision report 2006 Jupiter research, http://www.jupiterresearch.com ; solicitado por silverpon. Diciembre de 2006.
Successful Direct Marketing Methods, Bob Stone, Ron Jacobs, McGraw-Hill; 7th edition
Response: The Complete Guide to Profitable Direct Marketing;Lois K. Geller; Oxford University Press, USA; Rev&Expand edition
Effective E-Mail Made E-Z: Practical Strategies for Strengthening Electronic Communication; Verne Meyer, Pat Sebranek, John Van Rys; Upwrite Press