APA (7th ed.) Citation

Chesterton, G. K. (1996). Heretics. Project Gutenberg.

Chicago Style (17th ed.) Citation

Chesterton, G. K. Heretics. Project Gutenberg, 1996.

MLA (9th ed.) Citation

Chesterton, G. K. Heretics. Project Gutenberg, 1996.

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