MLA

Byron, Robert, 1905-1941. The Geographical Magazine. Box 9, folder 160. 1940-1941. https://collections.library.yale.edu/catalog/17300506.

APA, 6th edition

Byron, Robert, 1905-1941. (["Box 9, folder 160"])(1940-1941)[The Geographical Magazine]. https://collections.library.yale.edu/catalog/17300506.