APA (7th ed.) Citation

Opler lhPaul & Malikul. A field guide to eastern butterflies.

Chicago Style (17th ed.) Citation

Opler lhPaul and Malikul. A Field Guide to Eastern Butterflies. New York lbHoughton Mifflin lc1998.

MLA (9th ed.) Citation

Opler lhPaul and Malikul. A Field Guide to Eastern Butterflies.

Warning: These citations may not always be 100% accurate.