MLA

Acton, Harold, 1904-1994. Act XII. Quarrel between the Favourites. Box 1, folder 85. 1933 1941. https://collections.library.yale.edu/catalog/16604557.

APA, 6th edition

Acton, Harold, 1904-1994. (["Box 1, folder 85"])(1933 1941)[Act XII. Quarrel between the Favourites]. https://collections.library.yale.edu/catalog/16604557.