MLA
Hiles, Isaac. Letter from Isaac Hiles to "Dear Brothers". Hiles Was a Member of the 20th Iowa Infantry Regiment, Company I - 1884 (Photocopy). 1884. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 19, Folder 35. https://digital.library.emory.edu/purl/4579s4mx8k-cor.
APA, 6th edition
Hiles, I. (1884). Letter from Isaac Hiles to "Dear Brothers". Hiles was a member of the 20th Iowa Infantry Regiment, Company I - 1884 (photocopy) (Box 19, Folder 35) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/4579s4mx8k-cor.
Chicago
Hiles, Isaac. “Letter from Isaac Hiles to ‘Dear Brothers’. Hiles Was a Member of the 20th Iowa Infantry Regiment, Company I - 1884 (Photocopy).” Letters (correspondence). Civil War Collection, 1884. Box 19, Folder 35. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/4579s4mx8k-cor.