MLA
Krebbs, S. H., and Co. Scene in a Grapefruit Orchard, Florida : African Americans on Ladders in Grapefruit Trees [Hand Colored]. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 68. https://digital.library.emory.edu/purl/491fj6q5b7-cor.
APA, 6th edition
Krebbs, S. H., & C. Scene in a grapefruit orchard, Florida : African Americans on ladders in grapefruit trees [hand colored] (Box 68) [Postcards]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/491fj6q5b7-cor.
Chicago
Krebbs, S. H., and Co. “Scene in a Grapefruit Orchard, Florida : African Americans on Ladders in Grapefruit Trees [Hand Colored].” Postcards. Robert Langmuir African American Photograph Collection, n.d. Box 68. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/491fj6q5b7-cor.