MLA

Kissinger, Henry, 1923-2023. Halloween massacre. Box 212, folder 3. 1975. https://collections.library.yale.edu/catalog/12480953.

APA, 6th edition

Kissinger, Henry, 1923-2023. (["Box 212, folder 3"])(1975)[Halloween massacre]. https://collections.library.yale.edu/catalog/12480953.