MLA

Kissinger, Henry, 1923-2023. All Souls, Oxford. Box 343, folder 1. 1973. https://collections.library.yale.edu/catalog/11775135.

APA, 6th edition

Kissinger, Henry, 1923-2023. (["Box 343, folder 1"])(1973)[All Souls, Oxford]. https://collections.library.yale.edu/catalog/11775135.