"Zeszyt 4," notebook
MLA
Wat, Aleksander, 1900-1967. "Zeszyt 4," notebook. Box 33, folder 764. undated. https://collections.library.yale.edu/catalog/2054641.
APA, 6th edition
Wat, Aleksander, 1900-1967. (["Box 33, folder 764"])(undated)["Zeszyt 4," notebook]. https://collections.library.yale.edu/catalog/2054641.