MLA

Kissinger, Henry, 1923-2023. Armstrong, Hamilton Fish. Box 2, folder 19. 1961-1966. https://collections.library.yale.edu/catalog/11782318.

APA, 6th edition

Kissinger, Henry, 1923-2023. (["Box 2, folder 19"])(1961-1966)[Armstrong, Hamilton Fish]. https://collections.library.yale.edu/catalog/11782318.