MLA

Kissinger, Henry, 1923-2023. "The Elements of National Power," Army War College, Sep 4-5, 1957 [2 of 3]. Box 241, folder 15. 1957 June-October. https://collections.library.yale.edu/catalog/11786362.

APA, 6th edition

Kissinger, Henry, 1923-2023. (["Box 241, folder 15"])(1957 June-October)["The Elements of National Power," Army War College, Sep 4-5, 1957 [2 of 3]]. https://collections.library.yale.edu/catalog/11786362.