MLA

Williams, Jonathan, 1929-2008. Finn Byrhard. Box 37 | T0665. https://collections.library.yale.edu/catalog/2050706.

APA, 6th edition

Williams, Jonathan, 1929-2008. (["Box 37 | T0665"])[Finn Byrhard]. https://collections.library.yale.edu/catalog/2050706.