MLA
Solon. Letter from "Solon" (Milledgeville, Georgia) to "My Very Dear Wife" - January 23, 1861. 1861. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 5, Folder 62. https://digital.library.emory.edu/purl/262s4mw7r1-cor.
APA, 6th edition
S. (1861). Letter from "Solon" (Milledgeville, Georgia) to "My Very Dear Wife" - January 23, 1861 (Box 5, Folder 62) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/262s4mw7r1-cor.
Chicago
Solon. “Letter from ‘Solon’ (Milledgeville, Georgia) to ‘My Very Dear Wife’ - January 23, 1861.” Letters (correspondence). Civil War Collection, 1861. Box 5, Folder 62. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/262s4mw7r1-cor.