APA (7th ed.) Citation

Smith, E. E. (2007). Triplanetary. Project Gutenberg.

Chicago Style (17th ed.) Citation

Smith, E. E. Triplanetary. Project Gutenberg, 2007.

MLA (9th ed.) Citation

Smith, E. E. Triplanetary. Project Gutenberg, 2007.

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