MLA
Garber, J. R. Letter from J. R. Garber to His Mother, Mrs. A. M. Garber (Livingston, Alabama). Garber Served in the 8th Alabama Cavalry Regiment - December 30, 1864. 1864. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 3, Folder 30. https://digital.library.emory.edu/purl/627zkh19bk-cor.
APA, 6th edition
Garber, J. R. (1864). Letter from J. R. Garber to his mother, Mrs. A. M. Garber (Livingston, Alabama). Garber served in the 8th Alabama Cavalry Regiment - December 30, 1864 (Box 3, Folder 30) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/627zkh19bk-cor.
Chicago
Garber, J. R. “Letter from J. R. Garber to His Mother, Mrs. A. M. Garber (Livingston, Alabama). Garber Served in the 8th Alabama Cavalry Regiment - December 30, 1864.” Letters (correspondence). Civil War Collection, 1864. Box 3, Folder 30. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/627zkh19bk-cor.