Denton, D. K. (1990). How to give quality service to your customers. Universal.
Chicago Style aipamenaDenton, D. Keith. How to Give Quality Service to Your Customers. New Delhi: Universal, 1990.
MLA aipamenaDenton, D. Keith. How to Give Quality Service to Your Customers. Universal, 1990.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.