MLA
Perine, George Edward, 1837-1885, Brady, Mathew B., approximately 1823-1896. Union general William Rosecrans. 1861?/1880?. Civil War Collection. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/5977sqvbzz-cor.
APA, 6th edition
Perine, George Edward, 1837-1885, & Brady, Mathew B., approximately 1823-1896. (1861?/1880?)[Union general William Rosecrans]. Civil War Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/5977sqvbzz-cor.
Chicago
Perine, George Edward, 1837-1885, Brady, Mathew B., approximately 1823-1896, Union general William Rosecrans, 1861?/1880?, Civil War Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/5977sqvbzz-cor.