MLA

Wilder, Thornton, 1897-1975. Manuscript notebook: Act III. Box 91, folder 2311. n.d.. https://collections.library.yale.edu/catalog/17056677.

APA, 6th edition

Wilder, Thornton, 1897-1975. (["Box 91, folder 2311"])(n.d.)[Manuscript notebook: Act III]. https://collections.library.yale.edu/catalog/17056677.