MLA
Dowtin, Tom. Letter from Tom Dowtin, Resident of Cass County, Georgia Who Served in the 18th Georgia Infantry Regiment, to His Sister - November 28, 1861. 1861. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 3, Folder 10. https://digital.library.emory.edu/purl/948sbcc3h0-cor.
APA, 6th edition
Dowtin, T. (1861). Letter from Tom Dowtin, resident of Cass County, Georgia who served in the 18th Georgia Infantry Regiment, to his sister - November 28, 1861 (Box 3, Folder 10) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/948sbcc3h0-cor.
Chicago
Dowtin, Tom. “Letter from Tom Dowtin, Resident of Cass County, Georgia Who Served in the 18th Georgia Infantry Regiment, to His Sister - November 28, 1861.” Letters (correspondence). Civil War Collection, 1861. Box 3, Folder 10. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/948sbcc3h0-cor.