MLA
Rieder, M. Darby and Joan : Painting of an African American Man and Woman Sitting next to a Brick Wall. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 72. https://digital.library.emory.edu/purl/1504xgxd41-cor.
APA, 6th edition
Rieder, M. Darby and Joan : painting of an African American man and woman sitting next to a brick wall (Box 72) [Postcards]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/1504xgxd41-cor.
Chicago
Rieder, M. “Darby and Joan : Painting of an African American Man and Woman Sitting next to a Brick Wall.” Postcards. Robert Langmuir African American Photograph Collection, n.d. Box 72. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/1504xgxd41-cor.