MLA
Bungardt, H. F. Business Card Advertising Civil War Veterans the Services of Pension Attorney, H. F. Bungardt, in Kansas City, Missouri. 1870. Stuart A. Rose Manuscript, Archives, and Rare Book Library, Box 21, Folder 2. https://digital.library.emory.edu/purl/914nk98tnz-cor.
APA, 6th edition
Bungardt, H. F. (1870). Business card advertising Civil War veterans the services of pension attorney, H. F. Bungardt, in Kansas City, Missouri (Box 21, Folder 2) [Advertisements]. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/914nk98tnz-cor.
Chicago
Bungardt, H. F. “Business Card Advertising Civil War Veterans the Services of Pension Attorney, H. F. Bungardt, in Kansas City, Missouri.” Advertisements. Civil War Collection, 1870. Box 21, Folder 2. Stuart A. Rose Manuscript, Archives, and Rare Book Library. https://digital.library.emory.edu/purl/914nk98tnz-cor.