MLA

Stadler, Matthew, 1959-. Purdy article. Box 4. 1977 2011. https://collections.library.yale.edu/catalog/17310354.

APA, 6th edition

Stadler, Matthew, 1959-. (["Box 4"])(1977 2011)[Purdy article]. https://collections.library.yale.edu/catalog/17310354.