MLA
Piggott. Chief Catawan, Largest Human on Earth, Weight 693 Pounds. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 69. https://digital.library.emory.edu/purl/494vhhmgv6-cor.
APA, 6th edition
P. Chief Catawan, largest human on earth, weight 693 pounds (Box 69) [Photographic postcards]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/494vhhmgv6-cor.
Chicago
Piggott. “Chief Catawan, Largest Human on Earth, Weight 693 Pounds.” Photographic postcards. Robert Langmuir African American Photograph Collection, n.d. Box 69. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/494vhhmgv6-cor.