MLA
Lee, Fitzhugh, 1835-1905. Letter from Fitzhugh Lee (Richland, Virginia) to James Longstreet - July 4, 1879 (typescript). July 4, 1879. Civil War Collection. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/1848pk0q3h-cor.
APA, 6th edition
Lee, Fitzhugh, 1835-1905. (July 4, 1879)[Letter from Fitzhugh Lee (Richland, Virginia) to James Longstreet - July 4, 1879 (typescript)]. Civil War Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/1848pk0q3h-cor.
Chicago
Lee, Fitzhugh, 1835-1905, Letter from Fitzhugh Lee (Richland, Virginia) to James Longstreet - July 4, 1879 (typescript), July 4, 1879, Civil War Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/1848pk0q3h-cor.