MLA

Lynes, George Platt, 1907-1955. Datebook. Box 2, folder 18. 1955. https://collections.library.yale.edu/catalog/17422361.

APA, 6th edition

Lynes, George Platt, 1907-1955. (["Box 2, folder 18"])(1955)[Datebook]. https://collections.library.yale.edu/catalog/17422361.