MLA
Mize, T. A. Letter from T. A. Mize (Camp Sumter, Georgia) to "Dear Cousin" - May 5, 1864. 1864. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 5, Folder 22. https://digital.library.emory.edu/purl/10966t1h3p-cor.
APA, 6th edition
Mize, T. A. (1864). Letter from T. A. Mize (Camp Sumter, Georgia) to "Dear Cousin" - May 5, 1864 (Box 5, Folder 22) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/10966t1h3p-cor.
Chicago
Mize, T. A. “Letter from T. A. Mize (Camp Sumter, Georgia) to ‘Dear Cousin’ - May 5, 1864.” Letters (correspondence). Civil War Collection, 1864. Box 5, Folder 22. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/10966t1h3p-cor.