MLA

Drinkwater, John, 1882-1937. Lloyd-George, David Lloyd George, 1st earl, London. Box 5, folder 226. 1919 Sep 17. https://collections.library.yale.edu/catalog/17280589.

APA, 6th edition

Drinkwater, John, 1882-1937. (["Box 5, folder 226"])(1919 Sep 17)[Lloyd-George, David Lloyd George, 1st earl, London]. https://collections.library.yale.edu/catalog/17280589.