MLA

Johnson, James Weldon, 1871-1938. from Mildred L. Johnson. Box 42, folder 39. 1933-69. https://collections.library.yale.edu/catalog/17397033.

APA, 6th edition

Johnson, James Weldon, 1871-1938. (["Box 42, folder 39"])(1933-69)[from Mildred L. Johnson]. https://collections.library.yale.edu/catalog/17397033.