MLA

Graves, Henry Solon, 1871-1951. Personal. Box 37, folder 417-419. undated. https://collections.library.yale.edu/catalog/10013799.

APA, 6th edition

Graves, Henry Solon, 1871-1951. (["Box 37, folder 417-419"])(undated)[Personal]. https://collections.library.yale.edu/catalog/10013799.