MLA

Kissinger, Henry, 1923-2023. Greg-Gyll. Box 73, folder 4. 2003. https://collections.library.yale.edu/catalog/12481863.

APA, 6th edition

Kissinger, Henry, 1923-2023. (["Box 73, folder 4"])(2003)[Greg-Gyll]. https://collections.library.yale.edu/catalog/12481863.