MLA
Blackshear. Portrait of Man with Mustache in United States Volunteers Uniform. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 19. https://digital.library.emory.edu/purl/750tqjq2r7-cor.
APA, 6th edition
B. Portrait of man with mustache in United States Volunteers uniform (Box 19) [Card photographs (photographs)]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/750tqjq2r7-cor.
Chicago
Blackshear. “Portrait of Man with Mustache in United States Volunteers Uniform.” Card photographs (photographs). Langmuir Deposit - Sept 2020, n.d. Box 19. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/750tqjq2r7-cor.