APA (7th ed.) Citation

Smith, E. E. (2007). The Galaxy Primes. Project Gutenberg.

Chicago Style (17th ed.) Citation

Smith, E. E. The Galaxy Primes. Project Gutenberg, 2007.

MLA (9th ed.) Citation

Smith, E. E. The Galaxy Primes. Project Gutenberg, 2007.

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