MLA

Douglas, Norman, 1868-1952. "R" General. Box 45. 1929-1947, undated. https://collections.library.yale.edu/catalog/16454755.

APA, 6th edition

Douglas, Norman, 1868-1952. (["Box 45"])(1929-1947, undated)["R" General]. https://collections.library.yale.edu/catalog/16454755.