MLA

Canby, Henry Seidel, 1878-1961. Adulthood. Box 39, folder 906. 1941, n.d.. https://collections.library.yale.edu/catalog/2012570.

APA, 6th edition

Canby, Henry Seidel, 1878-1961. (["Box 39, folder 906"])(1941, n.d.)[Adulthood]. https://collections.library.yale.edu/catalog/2012570.