MLA

Johnson, James Weldon, 1871-1938. Johnson, Charles S.. Box 30, folder 96. 1935-56, undated. https://collections.library.yale.edu/catalog/31919366.

APA, 6th edition

Johnson, James Weldon, 1871-1938. (["Box 30, folder 96"])(1935-56, undated)[Johnson, Charles S.]. https://collections.library.yale.edu/catalog/31919366.