APA (7th ed.) Citation

Ferris, C. D., & Brown, F. M. (1981). Butterflies of the Rocky Mountain states. University of Oklahoma Press.

Chicago Style (17th ed.) Citation

Ferris, Clifford D., and F. Martin Brown. Butterflies of the Rocky Mountain States. Norman: University of Oklahoma Press, 1981.

MLA (9th ed.) Citation

Ferris, Clifford D., and F. Martin Brown. Butterflies of the Rocky Mountain States. University of Oklahoma Press, 1981.