MLA

Simpson, Randolph Linsly, 1927-1992. Centennial Photographic Co., Philadelphia Stamped recto, "Centennial Photographic Co. Philad'a. International Exhibition, 1876." Stamped verso, Centennial Photographic Company seal with senior officers listed.. Box 12, folder 537. circa 1876. https://collections.library.yale.edu/catalog/9999045.

APA, 6th edition

Simpson, Randolph Linsly, 1927-1992. (["Box 12, folder 537"])(circa 1876)[Centennial Photographic Co., Philadelphia Stamped recto, "Centennial Photographic Co. Philad'a. International Exhibition, 1876." Stamped verso, Centennial Photographic Company seal with senior officers listed.]. https://collections.library.yale.edu/catalog/9999045.