APA (7th ed.) Citation

Pettingill, O. S. (1981). A guide to bird finding west of the Mississippi (2nd ed.). Oxford University Press.

Chicago Style (17th ed.) Citation

Pettingill, Olin Sewall. A Guide to Bird Finding West of the Mississippi. 2nd ed. New York: Oxford University Press, 1981.

MLA (9th ed.) Citation

Pettingill, Olin Sewall. A Guide to Bird Finding West of the Mississippi. 2nd ed. Oxford University Press, 1981.