MLA
Speir, James H. Letter from James H. Speir to "Dear Sister" - March 24, 1876. 1876. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 6, Folder 53. https://digital.library.emory.edu/purl/095j9kd5rh-cor.
APA, 6th edition
Speir, J. H. (1876). Letter from James H. Speir to "Dear Sister" - March 24, 1876 (Box 6, Folder 53) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/095j9kd5rh-cor.
Chicago
Speir, James H. “Letter from James H. Speir to ‘Dear Sister’ - March 24, 1876.” Letters (correspondence). Civil War Collection, 1876. Box 6, Folder 53. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/095j9kd5rh-cor.