MLA
Kreeger, John M. Letter from John M. Kreeger (Fort Screven, Georgia), to [Illegible] - November 18, 1861. 1861. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 4, Folder 32. https://digital.library.emory.edu/purl/945cc2fs0x-cor.
APA, 6th edition
Kreeger, J. M. (1861). Letter from John M. Kreeger (Fort Screven, Georgia), to [illegible] - November 18, 1861 (Box 4, Folder 32) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/945cc2fs0x-cor.
Chicago
Kreeger, John M. “Letter from John M. Kreeger (Fort Screven, Georgia), to [Illegible] - November 18, 1861.” Letters (correspondence). Civil War Collection, 1861. Box 4, Folder 32. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/945cc2fs0x-cor.