Cita APA (7a ed.)

Nicolay, J. G., Hay, J., & Burlingame, M. (2007). Abraham Lincoln: The Observations of John G. Nicolay and John Hay. Southern Illinois University Press.

Cita Chicago Style (17a ed.)

Nicolay, John G., John Hay, y Michael Burlingame. Abraham Lincoln: The Observations of John G. Nicolay and John Hay. Carbondale: Southern Illinois University Press, 2007.

Cita MLA (8a ed.)

Nicolay, John G., et al. Abraham Lincoln: The Observations of John G. Nicolay and John Hay. Southern Illinois University Press, 2007.