Bopp, R. E., & Smith, L. C. (2011). Reference and information services: An introduction (4th ed.). Libraries Unlimited.
Chicago-viite (17. p.)Bopp, Richard E., ja Linda C. Smith. Reference and Information Services: An Introduction. 4th ed. Santa Barbara, Calif.: Libraries Unlimited, 2011.
MLA-viite (8. p.)Bopp, Richard E., ja Linda C. Smith. Reference and Information Services: An Introduction. 4th ed. Libraries Unlimited, 2011.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.