MLA

Camp, Walter, 1859-1925. Walter Camp with unidentified others. Box 62, folder 15 | reel 46U. undated. https://collections.library.yale.edu/catalog/10014886.

APA, 6th edition

Camp, Walter, 1859-1925. (["Box 62, folder 15 | reel 46U"])(undated)[Walter Camp with unidentified others]. https://collections.library.yale.edu/catalog/10014886.