MLA
Three Men Wearing and a Boy, with His Hand on One's Shoulder, All Wearing Hats. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 75. https://digital.library.emory.edu/purl/098z8w9gj2-cor.
APA, 6th edition
Three men wearing and a boy, with his hand on one's shoulder, all wearing hats (Box 75). [Photographic postcards]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/098z8w9gj2-cor.
Chicago
“Three Men Wearing and a Boy, with His Hand on One's Shoulder, All Wearing Hats.” Photographic postcards. Robert Langmuir African American Photograph Collection, n.d. Box 75. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/098z8w9gj2-cor.