MLA
Beware : a Dead African American Man Tied to a Post. 1918. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 70. https://digital.library.emory.edu/purl/255z612jqj-cor.
APA, 6th edition
Beware : a dead African American man tied to a post (Box 70). (1918). [Photographic postcards]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/255z612jqj-cor.
Chicago
“Beware : a Dead African American Man Tied to a Post.” Photographic postcards. Robert Langmuir African American Photograph Collection, 1918. Box 70. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/255z612jqj-cor.