MLA
Jennings, Solomon. Letter from Solomon Jennings (Virginia) to His Wife and Children. Solomon Jennings Served in the 45th Virginia Infantry Regiment - August 29, 1861. 1861. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 4, Folder 8. https://digital.library.emory.edu/purl/56341ns2tg-cor.
APA, 6th edition
Jennings, S. (1861). Letter from Solomon Jennings (Virginia) to his wife and children. Solomon Jennings served in the 45th Virginia Infantry Regiment - August 29, 1861 (Box 4, Folder 8) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/56341ns2tg-cor.
Chicago
Jennings, Solomon. “Letter from Solomon Jennings (Virginia) to His Wife and Children. Solomon Jennings Served in the 45th Virginia Infantry Regiment - August 29, 1861.” Letters (correspondence). Civil War Collection, 1861. Box 4, Folder 8. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/56341ns2tg-cor.