APA (7th ed.) Citation

Hudson, W. H. (2012). Birds in London. Project Gutenberg.

Chicago Style (17th ed.) Citation

Hudson, W. H. Birds in London. Project Gutenberg, 2012.

MLA (9th ed.) Citation

Hudson, W. H. Birds in London. Project Gutenberg, 2012.

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