MLA

Pound, Ezra, 1885-1972. Child, Clarence Griffin. Box 9, folder 392. 1932. https://collections.library.yale.edu/catalog/17122535.

APA, 6th edition

Pound, Ezra, 1885-1972. (["Box 9, folder 392"])(1932)[Child, Clarence Griffin]. https://collections.library.yale.edu/catalog/17122535.