MLA

Argus Book Shop (Chicago, Ill.). Casey, Robert J. (Robert Joseph). Box 2, folder 71. 1941-1943. https://collections.library.yale.edu/catalog/17411904.

APA, 6th edition

Argus Book Shop (Chicago, Ill.). (["Box 2, folder 71"])(1941-1943)[Casey, Robert J. (Robert Joseph)]. https://collections.library.yale.edu/catalog/17411904.