MLA
Hilton, Joseph. Letter from Joseph Hilton (Trenches near Richmond, Virginia) to His Cousin, Miss Lizzie Lachlison - October 14, 1864. 1864. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 3, Folder 59. https://digital.library.emory.edu/purl/914nk98tgk-cor.
APA, 6th edition
Hilton, J. (1864). Letter from Joseph Hilton (Trenches near Richmond, Virginia) to his cousin, Miss Lizzie Lachlison - October 14, 1864 (Box 3, Folder 59) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/914nk98tgk-cor.
Chicago
Hilton, Joseph. “Letter from Joseph Hilton (Trenches near Richmond, Virginia) to His Cousin, Miss Lizzie Lachlison - October 14, 1864.” Letters (correspondence). Civil War Collection, 1864. Box 3, Folder 59. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/914nk98tgk-cor.