MLA
Ahrens, Henry H. Mather School at Beaufort, South Carolina. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 69. https://digital.library.emory.edu/purl/962f7m0cm8-cor.
APA, 6th edition
Ahrens, H. H. Mather School at Beaufort, South Carolina (Box 69) [Postcards]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/962f7m0cm8-cor.
Chicago
Ahrens, Henry H. “Mather School at Beaufort, South Carolina.” Postcards. Robert Langmuir African American Photograph Collection, n.d. Box 69. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/962f7m0cm8-cor.