APA (7th ed.) Citation

Pycraft, W. P., & Green, R. (2014). Birds in Flight. Project Gutenberg.

Chicago Style (17th ed.) Citation

Pycraft, W. P., and Roland Green. Birds in Flight. Project Gutenberg, 2014.

MLA (9th ed.) Citation

Pycraft, W. P., and Roland Green. Birds in Flight. Project Gutenberg, 2014.

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