APA (7th ed.) Citation

Comstock, J. H. (1920). An introduction to entomology (9th ed. rev.). Cornell University Press.

Chicago Style (17th ed.) Citation

Comstock, John Henry. An Introduction to Entomology. 9th ed. rev. Ithaca, NY: Cornell University Press, 1920.

MLA (9th ed.) Citation

Comstock, John Henry. An Introduction to Entomology. 9th ed. rev. Cornell University Press, 1920.