MLA

Brooks, Cleanth, 1906-1994. McLuhan, Marshall. Box 7, folder 182-83. 1945-49. https://collections.library.yale.edu/catalog/17103605.

APA, 6th edition

Brooks, Cleanth, 1906-1994. (["Box 7, folder 182-83"])(1945-49)[McLuhan, Marshall]. https://collections.library.yale.edu/catalog/17103605.