APA (7th ed.) Citation

Muir, J. (2004). The Grand Cañon of the Colorado. Project Gutenberg.

Chicago Style (17th ed.) Citation

Muir, John. The Grand Cañon of the Colorado. Project Gutenberg, 2004.

MLA (9th ed.) Citation

Muir, John. The Grand Cañon of the Colorado. Project Gutenberg, 2004.

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