MLA
Dittmeyer, W. E. The U.S. Armory Buildings Which John Brown Took Possession of, Junction of Md., Va. and W. Va. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 69. https://digital.library.emory.edu/purl/515bcc2fv5-cor.
APA, 6th edition
Dittmeyer, W. E. The U.S. Armory buildings which John Brown took possession of, junction of Md., Va. and W. Va. (Box 69) [Postcards]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/515bcc2fv5-cor.
Chicago
Dittmeyer, W. E. “The U.S. Armory Buildings Which John Brown Took Possession of, Junction of Md., Va. and W. Va.” 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/515bcc2fv5-cor.