APA (7th ed.) Citation

Burroughs, E. R. (2011). A Princess of Mars. Project Gutenberg.

Chicago Style (17th ed.) Citation

Burroughs, Edgar Rice. A Princess of Mars. Project Gutenberg, 2011.

MLA (9th ed.) Citation

Burroughs, Edgar Rice. A Princess of Mars. Project Gutenberg, 2011.

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