Bopp, R. E., & Smith, L. C. (2001). Reference and information services: An Introduction (3rd ed.). Libraries Unlimited.
Παραπομπή Chicago StyleBopp, Richard E., και Linda C. Smith. Reference and Information Services: An Introduction. 3rd ed. Englewood, Colorado: Libraries Unlimited, 2001.
Παραπομπή MLABopp, Richard E., και Linda C. Smith. Reference and Information Services: An Introduction. 3rd ed. Libraries Unlimited, 2001.
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