MLA

Kissinger, Henry, 1923-2023. Nixon, Richard. Box 573, folder 10. 1989. https://collections.library.yale.edu/catalog/11779724.

APA, 6th edition

Kissinger, Henry, 1923-2023. (["Box 573, folder 10"])(1989)[Nixon, Richard]. https://collections.library.yale.edu/catalog/11779724.