MLA
Portrait of Peter Williams, an Ex-Slave Clergyman. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 74. https://digital.library.emory.edu/purl/9117m0cg1n-cor.
APA, 6th edition
Portrait of Peter Williams, an ex-slave clergyman (Box 74). [Photographic postcards]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/9117m0cg1n-cor.
Chicago
“Portrait of Peter Williams, an Ex-Slave Clergyman.” Photographic postcards. Robert Langmuir African American Photograph Collection, n.d. Box 74. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/9117m0cg1n-cor.