MLA

Perlin, Bernard, 1918-2014. Sketchbooks. Box 20 (Oversize). undated. https://collections.library.yale.edu/catalog/12200777.

APA, 6th edition

Perlin, Bernard, 1918-2014. (["Box 20 (Oversize)"])(undated)[Sketchbooks]. https://collections.library.yale.edu/catalog/12200777.