MLA
Williams, Lillie Burress. Letter from Lillie Burress Williams Describing Letters Written by Her Relative, William Wesley Welborn (Typescript). 1939. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 7, Folder 17. https://digital.library.emory.edu/purl/706g1jwtwm-cor.
APA, 6th edition
Williams, L. B. (1939). Letter from Lillie Burress Williams describing letters written by her relative, William Wesley Welborn (typescript) (Box 7, Folder 17) [Documents (object genre)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/706g1jwtwm-cor.
Chicago
Williams, Lillie Burress. “Letter from Lillie Burress Williams Describing Letters Written by Her Relative, William Wesley Welborn (Typescript).” Documents (object genre). Civil War Collection, 1939. Box 7, Folder 17. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/706g1jwtwm-cor.