APA (7th ed.) Citation

Sibley, D. A. (2009). The Sibley guide to trees. Alfred A. Knopf.

Chicago Style (17th ed.) Citation

Sibley, David Allen. The Sibley Guide to Trees. New York: Alfred A. Knopf, 2009.

MLA (9th ed.) Citation

Sibley, David Allen. The Sibley Guide to Trees. Alfred A. Knopf, 2009.

Warning: These citations may not always be 100% accurate.