APA (7th ed.) Citation

Sibley, D. (2003). The Sibley field guide to birds of western North America. Knopf.

Chicago Style (17th ed.) Citation

Sibley, David. The Sibley Field Guide to Birds of Western North America. New York: Knopf, 2003.

MLA (9th ed.) Citation

Sibley, David. The Sibley Field Guide to Birds of Western North America. Knopf, 2003.