MLA

Douglas, Norman, 1868-1952. Douglas and friends. Box 34, folder 564. undated. https://collections.library.yale.edu/catalog/32261725.

APA, 6th edition

Douglas, Norman, 1868-1952. (["Box 34, folder 564"])(undated)[Douglas and friends]. https://collections.library.yale.edu/catalog/32261725.