MLA

Kissinger, Henry, 1923-2023. Correspondence. Box 261, folder 5. 1957 August-September. https://collections.library.yale.edu/catalog/11786743.

APA, 6th edition

Kissinger, Henry, 1923-2023. (["Box 261, folder 5"])(1957 August-September)[Correspondence]. https://collections.library.yale.edu/catalog/11786743.