MLA

Kissinger, Henry, 1923-2023. Birnbaum, Karl. Box 120, folder 19. 1964-1967. https://collections.library.yale.edu/catalog/11784455.

APA, 6th edition

Kissinger, Henry, 1923-2023. (["Box 120, folder 19"])(1964-1967)[Birnbaum, Karl]. https://collections.library.yale.edu/catalog/11784455.