APA (7th ed.) Citation

O'Brien, F. J. (2007). The Diamond Lens. Project Gutenberg.

Chicago Style (17th ed.) Citation

O'Brien, Fitz James. The Diamond Lens. Project Gutenberg, 2007.

MLA (9th ed.) Citation

O'Brien, Fitz James. The Diamond Lens. Project Gutenberg, 2007.

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