MLA
Henrietta. Letter from "Henrietta" (Lansing, Michigan) to "Friend Boutell," (Lansing Michigan) - November 5, 1876. 1876. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 19, Folder 8. https://digital.library.emory.edu/purl/866vx0k7kk-cor.
APA, 6th edition
H. (1876). Letter from "Henrietta" (Lansing, Michigan) to "Friend Boutell," (Lansing Michigan) - November 5, 1876 (Box 19, Folder 8) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/866vx0k7kk-cor.
Chicago
Henrietta. “Letter from ‘Henrietta’ (Lansing, Michigan) to ‘Friend Boutell," (Lansing Michigan) - November 5, 1876.” Letters (correspondence). Civil War Collection, 1876. Box 19, Folder 8. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/866vx0k7kk-cor.