MLA

Kissinger, Henry, 1923-2023. Sp. Box 446, folder 9. 1981. https://collections.library.yale.edu/catalog/11777919.

APA, 6th edition

Kissinger, Henry, 1923-2023. (["Box 446, folder 9"])(1981)[Sp]. https://collections.library.yale.edu/catalog/11777919.