MLA

Cassirer, Ernst, 1874-1945. Draft B, typescript, carbon, corrected. Box 11, folder 209. n.d.. https://collections.library.yale.edu/catalog/17274591.

APA, 6th edition

Cassirer, Ernst, 1874-1945. (["Box 11, folder 209"])(n.d.)[Draft B, typescript, carbon, corrected]. https://collections.library.yale.edu/catalog/17274591.