MLA

Keller, Deane, 1901-1992. Rome [American Academy]. Box 1, folder 10. 1922-1923, undated. https://collections.library.yale.edu/catalog/10015662.

APA, 6th edition

Keller, Deane, 1901-1992. (["Box 1, folder 10"])(1922-1923, undated)[Rome [American Academy]]. https://collections.library.yale.edu/catalog/10015662.