MLA

Kissinger, Henry, 1923-2023. Messages sent, Pa-Pr. Box 151, folder 8. 1969-1973. https://collections.library.yale.edu/catalog/12479775.

APA, 6th edition

Kissinger, Henry, 1923-2023. (["Box 151, folder 8"])(1969-1973)[Messages sent, Pa-Pr]. https://collections.library.yale.edu/catalog/12479775.