MLA

Kissinger, Henry, 1923-2023. Perkins, Roswell B.. Box 151, folder 5. 1961-1962 March. https://collections.library.yale.edu/catalog/11785008.

APA, 6th edition

Kissinger, Henry, 1923-2023. (["Box 151, folder 5"])(1961-1962 March)[Perkins, Roswell B.]. https://collections.library.yale.edu/catalog/11785008.