MLA

Kissinger, Henry, 1923-2023. Carstens, Karl with Kissinger. Box 785, folder 7. Undated, circa 1954-circa 2002. https://collections.library.yale.edu/catalog/11777096.

APA, 6th edition

Kissinger, Henry, 1923-2023. (["Box 785, folder 7"])(Undated, circa 1954-circa 2002)[Carstens, Karl with Kissinger]. https://collections.library.yale.edu/catalog/11777096.