MLA

Kissinger, Henry, 1923-2023. Zinner, Paul E., "Politics in Eastern Europe: Poland, Czechoslovakia, Hungary" (B-3). Box 165, folder 9. Circa 1959-circa 1960. https://collections.library.yale.edu/catalog/11785291.

APA, 6th edition

Kissinger, Henry, 1923-2023. (["Box 165, folder 9"])(Circa 1959-circa 1960)[Zinner, Paul E., "Politics in Eastern Europe: Poland, Czechoslovakia, Hungary" (B-3)]. https://collections.library.yale.edu/catalog/11785291.