MLA

Van Thal, Herbert, 1904-1983. Osborne, Eric. Box 1, folder 88. 1958-59, n.d.. https://collections.library.yale.edu/catalog/16545992.

APA, 6th edition

Van Thal, Herbert, 1904-1983. (["Box 1, folder 88"])(1958-59, n.d.)[Osborne, Eric]. https://collections.library.yale.edu/catalog/16545992.