MLA

Kissinger, Henry, 1923-2023. von Guttenberg, Karl. Box 61, folder 15. 1964-1968. https://collections.library.yale.edu/catalog/11783570.

APA, 6th edition

Kissinger, Henry, 1923-2023. (["Box 61, folder 15"])(1964-1968)[von Guttenberg, Karl]. https://collections.library.yale.edu/catalog/11783570.