Peppers. Don ; Rogers, M. (2005). Return on Customer. Happer Business.
Chicago Style aipamenaPeppers. Don ; Rogers, Martha. Return on Customer. New York: Happer Business, 2005.
MLA aipamenaPeppers. Don ; Rogers, Martha. Return on Customer. Happer Business, 2005.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.