APA-referens (7:e uppl.)

Humphrey, D. B., Keppler, R., & Montes-Negret, F. (1997). Cost recovery and pricing of payment services: Theory, methods, and experience. World Bank.

Chicago-referens (17:e uppl.)

Humphrey, David B., Robert Keppler, och Fernando Montes-Negret. Cost Recovery and Pricing of Payment Services: Theory, Methods, and Experience. Washington, DC: World Bank, 1997.

MLA-referens (9:e uppl.)

Humphrey, David B., et al. Cost Recovery and Pricing of Payment Services: Theory, Methods, and Experience. World Bank, 1997.