MLA

Stein, Gertrude, 1874-1946. Conference Press. Box 102, folder 1984. 1940 Jul 30. https://collections.library.yale.edu/catalog/32247982.

APA, 6th edition

Stein, Gertrude, 1874-1946. (["Box 102, folder 1984"])(1940 Jul 30)[Conference Press]. https://collections.library.yale.edu/catalog/32247982.