APA (7th ed.) Citation

Adams, J., Adams, A., & Shuffelton, F. (2004). The letters of John and Abigail Adams. Penguin Books.

Chicago Style (17th ed.) Citation

Adams, John, Abigail Adams, and Frank Shuffelton. The Letters of John and Abigail Adams. New York, N.Y.: Penguin Books, 2004.

MLA (9th ed.) Citation

Adams, John, et al. The Letters of John and Abigail Adams. Penguin Books, 2004.