APA (7th ed.) Citation

Audubon, J. J. (2013). A Synopsis of the Birds of North America. Project Gutenberg.

Chicago Style (17th ed.) Citation

Audubon, John James. A Synopsis of the Birds of North America. Project Gutenberg, 2013.

MLA (9th ed.) Citation

Audubon, John James. A Synopsis of the Birds of North America. Project Gutenberg, 2013.

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