APA (7th ed.) Citation

Arnold, I. N. (2011). Sketch of the life of Abraham Lincoln. Project Gutenberg.

Chicago Style (17th ed.) Citation

Arnold, Isaac Newton. Sketch of the Life of Abraham Lincoln. Project Gutenberg, 2011.

MLA (9th ed.) Citation

Arnold, Isaac Newton. Sketch of the Life of Abraham Lincoln. Project Gutenberg, 2011.

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