MLA
Co., E. C. Kropp. On a Country Road, Showing Cotton Fields. 1906. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 74. https://digital.library.emory.edu/purl/4300zpc88g-cor.
APA, 6th edition
Co., E. C. K. (1906). On a country road, showing cotton fields (Box 74) [Postcards]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/4300zpc88g-cor.
Chicago
Co., E.C. Kropp. “On a Country Road, Showing Cotton Fields.” Postcards. Robert Langmuir African American Photograph Collection, 1906. Box 74. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/4300zpc88g-cor.