MLA
Lewis, Samuel E. (Samuel Edwin), 1838-1917. Letter from Samuel E. Lewis (Washington, D. C.) to General William E. Mickle, Adjutant General of the United Confederate Veterans organization, (New Orleans, Louisiana), relating to United Confederate Veterans business - July 22, 1912. July 22, 1912. Civil War Collection. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/4881jwsvrz-cor.
APA, 6th edition
Lewis, Samuel E. (Samuel Edwin), 1838-1917. (July 22, 1912)[Letter from Samuel E. Lewis (Washington, D. C.) to General William E. Mickle, Adjutant General of the United Confederate Veterans organization, (New Orleans, Louisiana), relating to United Confederate Veterans business - July 22, 1912]. Civil War Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/4881jwsvrz-cor.
Chicago
Lewis, Samuel E. (Samuel Edwin), 1838-1917, Letter from Samuel E. Lewis (Washington, D. C.) to General William E. Mickle, Adjutant General of the United Confederate Veterans organization, (New Orleans, Louisiana), relating to United Confederate Veterans business - July 22, 1912, July 22, 1912, Civil War Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/4881jwsvrz-cor.