APA (7th ed.) Citation

Holland, W. J. (2012). The Butterfly Book A Popular Guide to a Knowledge of the Butterflies of North America. Project Gutenberg.

Chicago Style (17th ed.) Citation

Holland, William Jacob. The Butterfly Book A Popular Guide to a Knowledge of the Butterflies of North America. Project Gutenberg, 2012.

MLA (9th ed.) Citation

Holland, William Jacob. The Butterfly Book A Popular Guide to a Knowledge of the Butterflies of North America. Project Gutenberg, 2012.

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