APA (7th ed.) Citation

Comstock, J. A., Emmel, T. C., & Emmel, J. F. (1989). Butterflies of California. Scientific Publishers.

Chicago Style (17th ed.) Citation

Comstock, John A., Thomas C. Emmel, and John F. Emmel. Butterflies of California. Gainesville, FL: Scientific Publishers, 1989.

MLA (9th ed.) Citation

Comstock, John A., et al. Butterflies of California. Scientific Publishers, 1989.