APA-referens (7:e uppl.)

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

Chicago-referens (17:e uppl.)

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

MLA-referens (8:e uppl.)

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