MLA

Canby, Henry Seidel, 1878-1961. DeVoto, Bernard. Box 2, folder 58. 1931-51, n.d.. https://collections.library.yale.edu/catalog/17170197.

APA, 6th edition

Canby, Henry Seidel, 1878-1961. (["Box 2, folder 58"])(1931-51, n.d.)[DeVoto, Bernard]. https://collections.library.yale.edu/catalog/17170197.