MLA

Kissinger, Henry, 1923-2023. Y. Box 557, folder 2. 1986. https://collections.library.yale.edu/catalog/11779516.

APA, 6th edition

Kissinger, Henry, 1923-2023. (["Box 557, folder 2"])(1986)[Y]. https://collections.library.yale.edu/catalog/11779516.