APA (7th ed.) Citation

Diffin, C. W. (2009). The Hammer of Thor. Project Gutenberg.

Chicago Style (17th ed.) Citation

Diffin, Charles Willard. The Hammer of Thor. Project Gutenberg, 2009.

MLA (9th ed.) Citation

Diffin, Charles Willard. The Hammer of Thor. Project Gutenberg, 2009.

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