APA (7th ed.) Citation

Harris, W. S. (2005). Life in a Thousand Worlds. Project Gutenberg.

Chicago Style (17th ed.) Citation

Harris, W. S. Life in a Thousand Worlds. Project Gutenberg, 2005.

MLA (9th ed.) Citation

Harris, W. S. Life in a Thousand Worlds. Project Gutenberg, 2005.

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