MLA
Wheeler, Joseph, 1836-1906. Note from Joseph Wheeler to L. Perry, vouching for General [Benjamin F.?] Kelley - November 28, 1889. November 28, 1889. Civil War Collection. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/750tqjq3dq-cor.
APA, 6th edition
Wheeler, Joseph, 1836-1906. (November 28, 1889)[Note from Joseph Wheeler to L. Perry, vouching for General [Benjamin F.?] Kelley - November 28, 1889]. Civil War Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/750tqjq3dq-cor.
Chicago
Wheeler, Joseph, 1836-1906, Note from Joseph Wheeler to L. Perry, vouching for General [Benjamin F.?] Kelley - November 28, 1889, November 28, 1889, Civil War Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/750tqjq3dq-cor.