MLA
Manley, John Washington Jeremiah. Letter from Joseph W. Manley (Camp near Fairfield, Alabama) to Catherine Chase. Manley Served in Company H of the 34th Georgia Infantry Regiment - June 5, 1863. 1863. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 4, Folder 57. https://digital.library.emory.edu/purl/3009w0vv58-cor.
APA, 6th edition
Manley, J. W. J. (1863). Letter from Joseph W. Manley (Camp near Fairfield, Alabama) to Catherine Chase. Manley served in Company H of the 34th Georgia Infantry Regiment - June 5, 1863 (Box 4, Folder 57) [Letters (correspondence)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/3009w0vv58-cor.
Chicago
Manley, John Washington Jeremiah. “Letter from Joseph W. Manley (Camp near Fairfield, Alabama) to Catherine Chase. Manley Served in Company H of the 34th Georgia Infantry Regiment - June 5, 1863.” Letters (correspondence). Civil War Collection, 1863. Box 4, Folder 57. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/3009w0vv58-cor.