APA (7th ed.) Citation

Gregor, E. R. (2011). Three Sioux Scouts. Project Gutenberg.

Chicago Style (17th ed.) Citation

Gregor, Elmer Russell. Three Sioux Scouts. Project Gutenberg, 2011.

MLA (9th ed.) Citation

Gregor, Elmer Russell. Three Sioux Scouts. Project Gutenberg, 2011.

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