MLA
Hall, John A. Letter from John A. Hall (Richmond, Virginia) to A. M. Morrow. Hall Served in Company H., 26th Alabama Infantry Regiment - May 15, 1862. 1862. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 3, Folder 45. https://digital.library.emory.edu/purl/153jwstrkm-cor.
APA, 6th edition
Hall, J. A. (1862). Letter from John A. Hall (Richmond, Virginia) to A. M. Morrow. Hall served in Company H., 26th Alabama Infantry Regiment - May 15, 1862 (Box 3, Folder 45) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/153jwstrkm-cor.
Chicago
Hall, John A. “Letter from John A. Hall (Richmond, Virginia) to A. M. Morrow. Hall Served in Company H., 26th Alabama Infantry Regiment - May 15, 1862.” Letters (correspondence). Civil War Collection, 1862. Box 3, Folder 45. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/153jwstrkm-cor.