APA (7th ed.) Citation

Chesterton, G. K. (2004). Twelve Types. Project Gutenberg.

Chicago Style (17th ed.) Citation

Chesterton, G. K. Twelve Types. Project Gutenberg, 2004.

MLA (9th ed.) Citation

Chesterton, G. K. Twelve Types. Project Gutenberg, 2004.

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