Douglass, R. C. (1960). The foraminiferal genus Orbitolina in North America: A study of the genus Orbitolina, its type species, morphology, and stratigraphic and geographic distribution in North America. U.S. Govt. Print. Off.
Chicago Style (17th ed.) CitationDouglass, Raymond C. The Foraminiferal Genus Orbitolina in North America: A Study of the Genus Orbitolina, Its Type Species, Morphology, and Stratigraphic and Geographic Distribution in North America. Washington: U.S. Govt. Print. Off, 1960.
MLA (9th ed.) CitationDouglass, Raymond C. The Foraminiferal Genus Orbitolina in North America: A Study of the Genus Orbitolina, Its Type Species, Morphology, and Stratigraphic and Geographic Distribution in North America. U.S. Govt. Print. Off, 1960.
Warning: These citations may not always be 100% accurate.