MLA

Kissinger, Henry, 1923-2023. Boyer, Louise. Box 198, folder 13. 1968 March. https://collections.library.yale.edu/catalog/11785815.

APA, 6th edition

Kissinger, Henry, 1923-2023. (["Box 198, folder 13"])(1968 March)[Boyer, Louise]. https://collections.library.yale.edu/catalog/11785815.