MLA

Kissinger, Henry, 1923-2023. Po. Box 111, folder 2. 2004-2006. https://collections.library.yale.edu/catalog/12480072.

APA, 6th edition

Kissinger, Henry, 1923-2023. (["Box 111, folder 2"])(2004-2006)[Po]. https://collections.library.yale.edu/catalog/12480072.