MLA
Picking Cotton : Two African American Women and an African American Boy and African American Girl in a Field Picking Cotton with Basket Filled with Cotton. 1907. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 68. https://digital.library.emory.edu/purl/624jm63xw8-cor.
APA, 6th edition
Picking cotton : two African American women and an African American boy and African American girl in a field picking cotton with basket filled with cotton (Box 68). (1907). [Photographic postcards]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/624jm63xw8-cor.
Chicago
“Picking Cotton : Two African American Women and an African American Boy and African American Girl in a Field Picking Cotton with Basket Filled with Cotton.” Photographic postcards. Robert Langmuir African American Photograph Collection, 1907. Box 68. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/624jm63xw8-cor.