MLA

Anderson, Margaret C., 1886-1973. Ray, Man. Box 18, folder 328. undated. https://collections.library.yale.edu/catalog/2020080.

APA, 6th edition

Anderson, Margaret C., 1886-1973. (["Box 18, folder 328"])(undated)[Ray, Man]. https://collections.library.yale.edu/catalog/2020080.