MLA

Kissinger, Henry, 1923-2023. Army. Box 2, folder 21. 1956-1959. https://collections.library.yale.edu/catalog/11782320.

APA, 6th edition

Kissinger, Henry, 1923-2023. (["Box 2, folder 21"])(1956-1959)[Army]. https://collections.library.yale.edu/catalog/11782320.