MLA

Wilder, Thornton, 1897-1975. Wilder, Isabel. Box 5, folder 113-119. 1946-48. https://collections.library.yale.edu/catalog/17056637.

APA, 6th edition

Wilder, Thornton, 1897-1975. (["Box 5, folder 113-119"])(1946-48)[Wilder, Isabel]. https://collections.library.yale.edu/catalog/17056637.