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.
Precaución: Estas citas no son 100% exactas.