MLA

Wilder, Thornton, 1897-1975. Playbill annotated by Wilder. Box 83, folder 2144. n.d.. https://collections.library.yale.edu/catalog/17056675.

APA, 6th edition

Wilder, Thornton, 1897-1975. (["Box 83, folder 2144"])(n.d.)[Playbill annotated by Wilder]. https://collections.library.yale.edu/catalog/17056675.