MLA

Bird, William, 1888-1963. Bedford, Agnes. Box 1, folder 2. 1922-24, n.d.. https://collections.library.yale.edu/catalog/17158107.

APA, 6th edition

Bird, William, 1888-1963. (["Box 1, folder 2"])(1922-24, n.d.)[Bedford, Agnes]. https://collections.library.yale.edu/catalog/17158107.