Bopp, R. E., & Smith, L. C. (2011). Reference and information services: An introduction (4th ed.). Libraries Unlimited.
Chicago-čujuhus (17. p.)Bopp, Richard E., juo Linda C. Smith. Reference and Information Services: An Introduction. 4th ed. Santa Barbara, Calif: Libraries Unlimited, 2011.
MLA-čujuhus (9. p.)Bopp, Richard E., juo Linda C. Smith. Reference and Information Services: An Introduction. 4th ed. Libraries Unlimited, 2011.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.