MLA

Lees-Milne, James, 1908-1997. Knollys, Eardley. Box 9, folder 435-437. 1958-91, n.d.. https://collections.library.yale.edu/catalog/17300579.

APA, 6th edition

Lees-Milne, James, 1908-1997. (["Box 9, folder 435-437"])(1958-91, n.d.)[Knollys, Eardley]. https://collections.library.yale.edu/catalog/17300579.