MLA

Wat, Aleksander, 1900-1967. Notes by Paulina Wat, manuscript. Box 21, folder 453-454. 1970s. https://collections.library.yale.edu/catalog/16618836.

APA, 6th edition

Wat, Aleksander, 1900-1967. (["Box 21, folder 453-454"])(1970s)[Notes by Paulina Wat, manuscript]. https://collections.library.yale.edu/catalog/16618836.