APA (7th ed.) Citation

Hughes, W. A. (1968). The thecosomatous pteropods of the Gulf of Mexico. [publisher not identified].

Chicago Style (17th ed.) Citation

Hughes, William Arthur. The Thecosomatous Pteropods of the Gulf of Mexico. [College Station, Tex.]: [publisher not identified], 1968.

MLA (9th ed.) Citation

Hughes, William Arthur. The Thecosomatous Pteropods of the Gulf of Mexico. [publisher not identified], 1968.