APA (7th ed.) Citation

Mackenzie, D. A. (2013). Ancient Man in Britain. Project Gutenberg.

Chicago Style (17th ed.) Citation

Mackenzie, Donald A. Ancient Man in Britain. Project Gutenberg, 2013.

MLA (9th ed.) Citation

Mackenzie, Donald A. Ancient Man in Britain. Project Gutenberg, 2013.

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