APA (7th ed.) Citation

Life Books (Firm), Guelzo, A. C., & Gates, H. L., Jr. (2014). Lincoln: An intimate portrait. Life Books.

Chicago Style (17th ed.) Citation

Life Books (Firm), Allen C. Guelzo, and Henry Louis Gates, Jr. Lincoln: An Intimate Portrait. New York, N.Y.: Life Books, 2014.

MLA (8th ed.) Citation

Life Books (Firm), et al. Lincoln: An Intimate Portrait. Life Books, 2014.

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