APA (7th ed.) Citation

Silverberg, R., & Mack, S. (2008). Starman's Quest. Project Gutenberg.

Chicago Style (17th ed.) Citation

Silverberg, Robert, and Stan Mack. Starman's Quest. Project Gutenberg, 2008.

MLA (9th ed.) Citation

Silverberg, Robert, and Stan Mack. Starman's Quest. Project Gutenberg, 2008.

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