MLA
Scarborough, R. P. Letter from R. P. Scarborough (Petersburg, Virginia) to His Cousin Araminta Williams - January 31, 1865. 1865. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 6, Folder 13. https://digital.library.emory.edu/purl/53976hdrz6-cor.
APA, 6th edition
Scarborough, R. P. (1865). Letter from R. P. Scarborough (Petersburg, Virginia) to his cousin Araminta Williams - January 31, 1865 (Box 6, Folder 13) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/53976hdrz6-cor.
Chicago
Scarborough, R. P. “Letter from R. P. Scarborough (Petersburg, Virginia) to His Cousin Araminta Williams - January 31, 1865.” Letters (correspondence). Civil War Collection, 1865. Box 6, Folder 13. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/53976hdrz6-cor.