APA (7th ed.) Citation

Ernst, C. H., & Ernst, E. M. (2003). Snakes of the United States and Canada. Smithsonian Books.

Chicago Style (17th ed.) Citation

Ernst, Carl H., and Evelyn M. Ernst. Snakes of the United States and Canada. Washington, D.C.: Smithsonian Books, 2003.

MLA (9th ed.) Citation

Ernst, Carl H., and Evelyn M. Ernst. Snakes of the United States and Canada. Smithsonian Books, 2003.