Dyfyniad APA

Heffelfinger, C. H., & Weaver, R. B. (1939). Directed studies in world history. Mentzer, Bush & Co..

Dyfyniad Arddull Chicago

Heffelfinger, C. H., and Robert B. Weaver. Directed Studies in World History. New York ; Chicago: Mentzer, Bush & Co., 1939.

Dyfyniad MLA

Heffelfinger, C. H., and Robert B. Weaver. Directed Studies in World History. Mentzer, Bush & Co., 1939.

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