MLA

Camp, Walter, 1859-1925. Football: practice. Box 64, folder 38-42 | reel 46U. undated. https://collections.library.yale.edu/catalog/10012034.

APA, 6th edition

Camp, Walter, 1859-1925. (["Box 64, folder 38-42 | reel 46U"])(undated)[Football: practice]. https://collections.library.yale.edu/catalog/10012034.