MLA

Douglas, Norman, 1868-1952. "M" General. Box 45. 1942, 1947, undated. https://collections.library.yale.edu/catalog/16454743.

APA, 6th edition

Douglas, Norman, 1868-1952. (["Box 45"])(1942, 1947, undated)["M" General]. https://collections.library.yale.edu/catalog/16454743.