MLA
Kell, John McIntosh, 1823-1900. Letter from John McIntosh Kell (Georgia naval steamer "Savannah" at Darien, Georgia) to Adjutant-General Henry Constantine Wayne regarding the former's commision in the Navy of the State of Georgia - April 16, 1861. April 16, 1861. Civil War Collection. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/583kwh71sw-cor.
APA, 6th edition
Kell, John McIntosh, 1823-1900. (April 16, 1861)[Letter from John McIntosh Kell (Georgia naval steamer "Savannah" at Darien, Georgia) to Adjutant-General Henry Constantine Wayne regarding the former's commision in the Navy of the State of Georgia - April 16, 1861]. Civil War Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/583kwh71sw-cor.
Chicago
Kell, John McIntosh, 1823-1900, Letter from John McIntosh Kell (Georgia naval steamer "Savannah" at Darien, Georgia) to Adjutant-General Henry Constantine Wayne regarding the former's commision in the Navy of the State of Georgia - April 16, 1861, April 16, 1861, Civil War Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/583kwh71sw-cor.