MLA

Kissinger, Henry, 1923-2023. Barnett, Frank. Box 8, folder 2. 1968. https://collections.library.yale.edu/catalog/11782400.

APA, 6th edition

Kissinger, Henry, 1923-2023. (["Box 8, folder 2"])(1968)[Barnett, Frank]. https://collections.library.yale.edu/catalog/11782400.