Dittmann, H., & Hardy, J. (2007). Learn Library of Congress classification (2nd North American ed.). TotalRecall Publications, Inc..
Dyfyniad Arddull ChicagoDittmann, Helena, and Jane Hardy. Learn Library of Congress Classification. 2nd North American ed. Friendswood, Tex: TotalRecall Publications, Inc., 2007.
Dyfyniad MLADittmann, Helena, and Jane Hardy. Learn Library of Congress Classification. 2nd North American ed. TotalRecall Publications, Inc., 2007.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.