MLA

Edwards, Jonathan, 1703-1758. Backus, Azel. Box 26, folder 1427. 1801 Mar 4. https://collections.library.yale.edu/catalog/10956678.

APA, 6th edition

Edwards, Jonathan, 1703-1758. (["Box 26, folder 1427"])(1801 Mar 4)[Backus, Azel]. https://collections.library.yale.edu/catalog/10956678.