MLA

Kissinger, Henry, 1923-2023. Attachment to L-6853 dated April 7, 1967: "Note 1 - Re: Factors and Procedures Leading to Negotiations". Box 109, folder 2. Circa 1967 April. https://collections.library.yale.edu/catalog/11784251.

APA, 6th edition

Kissinger, Henry, 1923-2023. (["Box 109, folder 2"])(Circa 1967 April)[Attachment to L-6853 dated April 7, 1967: "Note 1 - Re: Factors and Procedures Leading to Negotiations"]. https://collections.library.yale.edu/catalog/11784251.