APA (7th ed.) Citation

Watson, S. (2006). The Mark of the Beast. Project Gutenberg.

Chicago Style (17th ed.) Citation

Watson, Sidney. The Mark of the Beast. Project Gutenberg, 2006.

MLA (9th ed.) Citation

Watson, Sidney. The Mark of the Beast. Project Gutenberg, 2006.

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