APA (7th ed.) Citation

Spellenberg, R. (1994). National Audubon Society field guide to North American wildflowers (13. printing.). Knopf.

Chicago Style (17th ed.) Citation

Spellenberg, Richard. National Audubon Society Field Guide to North American Wildflowers. 13. printing. New York: Knopf, 1994.

MLA (9th ed.) Citation

Spellenberg, Richard. National Audubon Society Field Guide to North American Wildflowers. 13. printing. Knopf, 1994.