APA (7th ed.) Citation

Turner, F. J. (2007). The Frontier in American History. Project Gutenberg.

Chicago Style (17th ed.) Citation

Turner, Frederick Jackson. The Frontier in American History. Project Gutenberg, 2007.

MLA (9th ed.) Citation

Turner, Frederick Jackson. The Frontier in American History. Project Gutenberg, 2007.

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