APA (7th ed.) Citation

Washington, G., Adams, J., Winthrop, J., & Adams, J. (1878). Letters from Washington to Heath.

Chicago Style (17th ed.) Citation

Washington, George, John Adams, John Winthrop, and John Adams. Letters from Washington to Heath. Boston, 1878.

MLA (9th ed.) Citation

Washington, George, et al. Letters from Washington to Heath. 1878.