MLA

Backus, Isaac, 1724-1806. Collected papers. box 9, folder 28. 1772 July–1772 August 22. https://collections.library.yale.edu/catalog/33578653.

APA, 6th edition

Backus, Isaac, 1724-1806. (["box 9, folder 28"])(1772 July–1772 August 22)[Collected papers]. https://collections.library.yale.edu/catalog/33578653.