MLA

Kissinger, Henry, 1923-2023. Grierson, Ronald. Box 26, folder 6. 1964-1968. https://collections.library.yale.edu/catalog/11782788.

APA, 6th edition

Kissinger, Henry, 1923-2023. (["Box 26, folder 6"])(1964-1968)[Grierson, Ronald]. https://collections.library.yale.edu/catalog/11782788.