APA (7th ed.) Citation

Lincoln, A., Barton, W. E., & William E. Barton Collection of Lincolniana. (1842). Marriage license of Abraham Lincoln and Mary Todd: Springfield, Ill.

Chicago Style (17th ed.) Citation

Lincoln, Abraham, William E. Barton, and William E. Barton Collection of Lincolniana. Marriage License of Abraham Lincoln and Mary Todd: Springfield, Ill. 1842.

MLA (8th ed.) Citation

Lincoln, Abraham, et al. Marriage License of Abraham Lincoln and Mary Todd: Springfield, Ill. 1842.