APA (7th ed.) Citation

Proctor, R. A. (2008). Myths and Marvels of Astronomy. Project Gutenberg.

Chicago Style (17th ed.) Citation

Proctor, Richard A. Myths and Marvels of Astronomy. Project Gutenberg, 2008.

MLA (9th ed.) Citation

Proctor, Richard A. Myths and Marvels of Astronomy. Project Gutenberg, 2008.

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