MLA
Libby Prison, the Only Picture in Existence, as It Appeared August 23, 1863. William A. Mountcastle, 1882. Stuart A. Rose Manuscript, Archives, and Rare Book Library, OP9, Folder 25. https://digital.library.emory.edu/purl/798mcvdpn2-cor.
APA, 6th edition
Libby Prison, the only picture in existence, as it appeared August 23, 1863 (OP9, Folder 25). (1882). [Lithographs]. William A. Mountcastle; Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/798mcvdpn2-cor.
Chicago
“Libby Prison, the Only Picture in Existence, as It Appeared August 23, 1863.” Lithographs. Civil War Collection. Richmond, VA: William A. Mountcastle, 1882. OP9, Folder 25. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/798mcvdpn2-cor.