APA (7th ed.) Citation

Carmichael, R. D. (2004). The Theory of Numbers. Project Gutenberg.

Chicago Style (17th ed.) Citation

Carmichael, R. D. The Theory of Numbers. Project Gutenberg, 2004.

MLA (9th ed.) Citation

Carmichael, R. D. The Theory of Numbers. Project Gutenberg, 2004.

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