MLA
Souvenir Post Card Co. (N.Y.). Cotton field : four African American men and an African American woman and African American girl picking cotton [hand colored]. unknown. Robert Langmuir African American Photograph Collection. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/651vdncjxh-cor.
APA, 6th edition
Souvenir Post Card Co. (N.Y.). (unknown)[Cotton field : four African American men and an African American woman and African American girl picking cotton [hand colored]]. Robert Langmuir African American Photograph Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/651vdncjxh-cor.
Chicago
Souvenir Post Card Co. (N.Y.), Cotton field : four African American men and an African American woman and African American girl picking cotton [hand colored], unknown, Robert Langmuir African American Photograph Collection, Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/651vdncjxh-cor.