MLA

Thistlewood, Thomas, 1721-1786. 20. Diary. Box 4, folder 20. 1769. https://collections.library.yale.edu/catalog/11864878.

APA, 6th edition

Thistlewood, Thomas, 1721-1786. (["Box 4, folder 20"])(1769)[20. Diary]. https://collections.library.yale.edu/catalog/11864878.