APA (7th ed.) Citation

Campbell, J. W. (2006). Invaders from the Infinite. Project Gutenberg.

Chicago Style (17th ed.) Citation

Campbell, John Wood. Invaders from the Infinite. Project Gutenberg, 2006.

MLA (9th ed.) Citation

Campbell, John Wood. Invaders from the Infinite. Project Gutenberg, 2006.

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