Cita APA

Ernst, C. H., & Barbour, R. W. 1. (1989). Turtles of the world. Washington: Smithsonian Institution.

Citación estilo Chicago

Ernst, Carl H., y Róger W. 1919- Barbour. Turtles of the World. Washington: Smithsonian Institution, 1989.

Cita MLA

Ernst, Carl H., y Róger W. 1919- Barbour. Turtles of the World. Washington: Smithsonian Institution, 1989.