Cassell, K. A., & Hiremath, U. (2009). Reference and information services in the 21st century: An introduction (2nd ed.). Neal-Schuman Publishers.
Dyfyniad Arddull ChicagoCassell, Kay Ann, and Uma Hiremath. Reference and Information Services in the 21st Century: An Introduction. 2nd ed. New York: Neal-Schuman Publishers, 2009.
Dyfyniad MLACassell, Kay Ann, and Uma Hiremath. Reference and Information Services in the 21st Century: An Introduction. 2nd ed. Neal-Schuman Publishers, 2009.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.