MLA
Brown, M. A. P. R. Letter from M. A. P. R. Brown to "Dear Friend Almira" - February 10, 1857 (Photocopy). 1857. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 19, Folder 35. https://digital.library.emory.edu/purl/327mpg4g7k-cor.
APA, 6th edition
Brown, M. A. P. R. (1857). Letter from M. A. P. R. Brown to "Dear Friend Almira" - February 10, 1857 (photocopy) (Box 19, Folder 35) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/327mpg4g7k-cor.
Chicago
Brown, M.A.P.R. “Letter from M. A. P. R. Brown to ‘Dear Friend Almira’ - February 10, 1857 (Photocopy).” Letters (correspondence). Civil War Collection, 1857. Box 19, Folder 35. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/327mpg4g7k-cor.