Bopp, R. E., & Smith, L. C. (2011). Reference and information services: An introduction (4th ed.). Libraries Unlimited.
Lua i Stíl Chicago (17ú heag.)Bopp, Richard E., agus Linda C. Smith. Reference and Information Services: An Introduction. 4th ed. Santa Barbara, Calif.: Libraries Unlimited, 2011.
Lua MLA (8ú heag.)Bopp, Richard E., agus Linda C. Smith. Reference and Information Services: An Introduction. 4th ed. Libraries Unlimited, 2011.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.