MLA
Neal, Moses. Letter from Moses Neal (Green County, Kentucky) to His Son, M. C. Neal - July 1, 1863. 1863. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 5, Folder 36. https://digital.library.emory.edu/purl/419s1rn9qj-cor.
APA, 6th edition
Neal, M. (1863). Letter from Moses Neal (Green County, Kentucky) to his son, M. C. Neal - July 1, 1863 (Box 5, Folder 36) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/419s1rn9qj-cor.
Chicago
Neal, Moses. “Letter from Moses Neal (Green County, Kentucky) to His Son, M. C. Neal - July 1, 1863.” Letters (correspondence). Civil War Collection, 1863. Box 5, Folder 36. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/419s1rn9qj-cor.