MLA

Ford, Charles Henri, 1908-2002. Nevelson, Louise. Box 4, folder 267. n.d.. https://collections.library.yale.edu/catalog/9998642.

APA, 6th edition

Ford, Charles Henri, 1908-2002. (["Box 4, folder 267"])(n.d.)[Nevelson, Louise]. https://collections.library.yale.edu/catalog/9998642.