MLA

Kissinger, Henry, 1923-2023. Messages sent, Es-Gu. Box 151, folder 5. 1969-1973. https://collections.library.yale.edu/catalog/12479887.

APA, 6th edition

Kissinger, Henry, 1923-2023. (["Box 151, folder 5"])(1969-1973)[Messages sent, Es-Gu]. https://collections.library.yale.edu/catalog/12479887.