MLA

Simpson, Randolph Linsly, 1927-1992. Keystone View Company, Meadville, PA; and other cities "109 - 314. Old Slave Market, St. Augustine, Florida." Stereograph, grey card. Box 13, folder 620. circa 1925. https://collections.library.yale.edu/catalog/32582568.

APA, 6th edition

Simpson, Randolph Linsly, 1927-1992. (["Box 13, folder 620"])(circa 1925)[Keystone View Company, Meadville, PA; and other cities "109 - 314. Old Slave Market, St. Augustine, Florida." Stereograph, grey card]. https://collections.library.yale.edu/catalog/32582568.