MLA

Kissinger, Henry, 1923-2023. Cheever, Daniel. Box 12, folder 20. 1963-1968. https://collections.library.yale.edu/catalog/11782503.

APA, 6th edition

Kissinger, Henry, 1923-2023. (["Box 12, folder 20"])(1963-1968)[Cheever, Daniel]. https://collections.library.yale.edu/catalog/11782503.