MLA

Brodsky, Joseph, 1940-1996. Pearson, Martha. Box 142, folder 3143. 1979. https://collections.library.yale.edu/catalog/2008157.

APA, 6th edition

Brodsky, Joseph, 1940-1996. (["Box 142, folder 3143"])(1979)[Pearson, Martha]. https://collections.library.yale.edu/catalog/2008157.