APA (7th ed.) Citation

Osborn, H. F. (2013). Men of the Old Stone Age Their Environment, Life and Art. Project Gutenberg.

Chicago Style (17th ed.) Citation

Osborn, Henry Fairfield. Men of the Old Stone Age Their Environment, Life and Art. Project Gutenberg, 2013.

MLA (9th ed.) Citation

Osborn, Henry Fairfield. Men of the Old Stone Age Their Environment, Life and Art. Project Gutenberg, 2013.

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