MLA

Anderson, Margaret C., 1886-1973. Kramer, Kent. Box 7, folder 108. 1969 March 21. https://collections.library.yale.edu/catalog/17099457.

APA, 6th edition

Anderson, Margaret C., 1886-1973. (["Box 7, folder 108"])(1969 March 21)[Kramer, Kent]. https://collections.library.yale.edu/catalog/17099457.