MLA

Du Bois, W. E. B. (William Edward Burghardt), 1868-1963. Printed poem "Easter Emancipation, 1863-1913" with holograph revisions,. Box 1, folder 20. n.d.. https://collections.library.yale.edu/catalog/16732022.

APA, 6th edition

Du Bois, W. E. B. (William Edward Burghardt), 1868-1963. (["Box 1, folder 20"])(n.d.)[Printed poem "Easter Emancipation, 1863-1913" with holograph revisions,]. https://collections.library.yale.edu/catalog/16732022.