APA (7th ed.) Citation

Geier, C. S. (2010). The Sphere of Sleep. Project Gutenberg.

Chicago Style (17th ed.) Citation

Geier, Chester S. The Sphere of Sleep. Project Gutenberg, 2010.

MLA (9th ed.) Citation

Geier, Chester S. The Sphere of Sleep. Project Gutenberg, 2010.

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