APA (7th ed.) Citation

Wallace, A. R. (2007). Contributions to the Theory of Natural Selection A Series of Essays. Project Gutenberg.

Chicago Style (17th ed.) Citation

Wallace, Alfred Russel. Contributions to the Theory of Natural Selection A Series of Essays. Project Gutenberg, 2007.

MLA (9th ed.) Citation

Wallace, Alfred Russel. Contributions to the Theory of Natural Selection A Series of Essays. Project Gutenberg, 2007.

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