Cita APA

Bopp, R. E., & Smith, L. C. (2011). Reference and information services: An introduction (4th ed.). Libraries Unlimited.

Citación estilo Chicago

Bopp, Richard E., and Linda C. Smith. Reference and Information Services: An Introduction. 4th ed. Santa Barbara, Calif.: Libraries Unlimited, 2011.

Cita MLA

Bopp, Richard E., and Linda C. Smith. Reference and Information Services: An Introduction. 4th ed. Libraries Unlimited, 2011.