MLA

Argus Book Shop (Chicago, Ill.). London, Jack. Box 7, folder 271. undated. https://collections.library.yale.edu/catalog/17411918.

APA, 6th edition

Argus Book Shop (Chicago, Ill.). (["Box 7, folder 271"])(undated)[London, Jack]. https://collections.library.yale.edu/catalog/17411918.