Dyfyniad APA

(1991). Reference and information services: An introduction. Englewood, Colorado: Libraries Unlimited, Inc.

Dyfyniad Arddull Chicago

Reference and Information Services: An Introduction. Englewood, Colorado: Libraries Unlimited, Inc, 1991.

Dyfyniad MLA

Reference and Information Services: An Introduction. Englewood, Colorado: Libraries Unlimited, Inc, 1991.

Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.