Cita APA (7th ed.)
Ehrlich, P. R., Ehrlich, A. H., & Bauer, D. L. [. o. s. (1961). How to know the butterflies: Illustrated keys for determining to species all butterflies found in North America, north of Mexico, with notes on their distribution, habits, and larval food, and suggestions for collecting and studying them. W. C. Brown Co.
Cita Chicago (17th ed.)
Ehrlich, Paul R., Anne H. Ehrlich, i D. L. [and others seven] Bauer. How to Know the Butterflies: Illustrated Keys for Determining to Species All Butterflies Found in North America, North of Mexico, with Notes on Their Distribution, Habits, and Larval Food, and Suggestions for Collecting and Studying Them. Dubuque, Iowa: W. C. Brown Co, 1961.
Cita MLA (9th ed.)
Ehrlich, Paul R., et al. How to Know the Butterflies: Illustrated Keys for Determining to Species All Butterflies Found in North America, North of Mexico, with Notes on Their Distribution, Habits, and Larval Food, and Suggestions for Collecting and Studying Them. W. C. Brown Co, 1961.
Atenció: Aquestes cites poden no estar 100% correctes.