MLA

Kissinger, Henry, 1923-2023. Jonker, Frederick. Box 33, folder 2. 1958, undated. https://collections.library.yale.edu/catalog/11782945.

APA, 6th edition

Kissinger, Henry, 1923-2023. (["Box 33, folder 2"])(1958, undated)[Jonker, Frederick]. https://collections.library.yale.edu/catalog/11782945.