MLA
Mahone, William, 1826-1895. Letter from William Mahone (Washington, D. C.) to Attorney General Benjamin Harrison Brewster, recommending John G. Watts for marshal; Mahone was a Confederate veteran and later a United States Senator from Virginia - March 9, 1882. March 9, 1882. Civil War Collection. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/064tht77k9-cor.
APA, 6th edition
Mahone, William, 1826-1895. (March 9, 1882)[Letter from William Mahone (Washington, D. C.) to Attorney General Benjamin Harrison Brewster, recommending John G. Watts for marshal; Mahone was a Confederate veteran and later a United States Senator from Virginia - March 9, 1882]. Civil War Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/064tht77k9-cor.
Chicago
Mahone, William, 1826-1895, Letter from William Mahone (Washington, D. C.) to Attorney General Benjamin Harrison Brewster, recommending John G. Watts for marshal; Mahone was a Confederate veteran and later a United States Senator from Virginia - March 9, 1882, March 9, 1882, Civil War Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/064tht77k9-cor.