MLA

Kissinger, Henry, 1923-2023. Richardson Foundation. Box 127, folder 7. 1955-1957 September. https://collections.library.yale.edu/catalog/11784564.

APA, 6th edition

Kissinger, Henry, 1923-2023. (["Box 127, folder 7"])(1955-1957 September)[Richardson Foundation]. https://collections.library.yale.edu/catalog/11784564.