MLA

Du Bois, W. E. B. (William Edward Burghardt), 1868-1963. Notes and miscellaneous pages. Box 4, folder 90-97. n.d.. https://collections.library.yale.edu/catalog/2040398.

APA, 6th edition

Du Bois, W. E. B. (William Edward Burghardt), 1868-1963. (["Box 4, folder 90-97"])(n.d.)[Notes and miscellaneous pages]. https://collections.library.yale.edu/catalog/2040398.