MLA

Kissinger, Henry, 1923-2023. Gredler, Willfried. Box 26, folder 1. 1960-1967. https://collections.library.yale.edu/catalog/11782783.

APA, 6th edition

Kissinger, Henry, 1923-2023. (["Box 26, folder 1"])(1960-1967)[Gredler, Willfried]. https://collections.library.yale.edu/catalog/11782783.