MLA

Wat, Aleksander, 1900-1967. "Zeszyt VII" (notes, essays), notebook and typescript. Box 32, folder 750-751. 1967, undated. https://collections.library.yale.edu/catalog/10512097.

APA, 6th edition

Wat, Aleksander, 1900-1967. (["Box 32, folder 750-751"])(1967, undated)["Zeszyt VII" (notes, essays), notebook and typescript]. https://collections.library.yale.edu/catalog/10512097.