MLA

Kissinger, Henry, 1923-2023. Helms, Richard. Box 415, folder 8. 1978 January-September. https://collections.library.yale.edu/catalog/11777514.

APA, 6th edition

Kissinger, Henry, 1923-2023. (["Box 415, folder 8"])(1978 January-September)[Helms, Richard]. https://collections.library.yale.edu/catalog/11777514.