MLA

Du Bois, W. E. B. (William Edward Burghardt), 1868-1963. Viking Press. Box 1, folder 14. 1946 Jun. https://collections.library.yale.edu/catalog/2040337.

APA, 6th edition

Du Bois, W. E. B. (William Edward Burghardt), 1868-1963. (["Box 1, folder 14"])(1946 Jun)[Viking Press]. https://collections.library.yale.edu/catalog/2040337.