MLA

Kissinger, Henry, 1923-2023. Coppieters, Emmanuel. Box 14, folder 5. 1957-1969. https://collections.library.yale.edu/catalog/11782534.

APA, 6th edition

Kissinger, Henry, 1923-2023. (["Box 14, folder 5"])(1957-1969)[Coppieters, Emmanuel]. https://collections.library.yale.edu/catalog/11782534.