MLA

Wat, Aleksander, 1900-1967. "Zeszyt 8," notebook. Box 33, folder 768. undated. https://collections.library.yale.edu/catalog/2054645.

APA, 6th edition

Wat, Aleksander, 1900-1967. (["Box 33, folder 768"])(undated)["Zeszyt 8," notebook]. https://collections.library.yale.edu/catalog/2054645.