MLA
Boxing Series : Jack Johnson, the World's Heavy-Weight Champion. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 74. https://digital.library.emory.edu/purl/276f1vhhpt-cor.
APA, 6th edition
Boxing series : Jack Johnson, the world's heavy-weight champion (Box 74). [Postcards]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/276f1vhhpt-cor.
Chicago
“Boxing Series : Jack Johnson, the World's Heavy-Weight Champion.” Postcards. Robert Langmuir African American Photograph Collection, n.d. Box 74. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/276f1vhhpt-cor.