Powell, G. R. (2002). Return on marketing investment: Demand more from your marketing and sales investments (1a. ed.). RPI.
Chicago Style (17th ed.) ZitazioaPowell, Guy R. Return on Marketing Investment: Demand More from Your Marketing and Sales Investments. 1a. ed. Albuquerque: RPI, 2002.
MLA (9th ed.) ZitazioaPowell, Guy R. Return on Marketing Investment: Demand More from Your Marketing and Sales Investments. 1a. ed. RPI, 2002.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.