MLA
Letter to Walter H. Clark from "Your Mother" - August 25, 1863. 1863. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 2, Folder 21. https://digital.library.emory.edu/purl/047rn8pkzz-cor.
APA, 6th edition
Letter to Walter H. Clark from "Your Mother" - August 25, 1863 (Box 2, Folder 21). (1863). [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/047rn8pkzz-cor.
Chicago
“Letter to Walter H. Clark from ‘Your Mother’ - August 25, 1863.” Letters (correspondence). Civil War Collection, 1863. Box 2, Folder 21. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/047rn8pkzz-cor.