MLA

Palmquist, Peter E. (1936-2003). Ambrotype in a case, of seven men, identified as prominent San Francisco businessmen. Box 45, folder 68. circa 1855-56. https://collections.library.yale.edu/catalog/2056732.

APA, 6th edition

Palmquist, Peter E. (1936-2003). (["Box 45, folder 68"])(circa 1855-56)[Ambrotype in a case, of seven men, identified as prominent San Francisco businessmen]. https://collections.library.yale.edu/catalog/2056732.