MLA

Edwards, Jonathan, 1703-1758. 1. Edwards, Eunice. Letter to Mary Edwards at Northampton.. Box 1, folder 1. Undated. https://collections.library.yale.edu/catalog/33223558.

APA, 6th edition

Edwards, Jonathan, 1703-1758. (["Box 1, folder 1"])(Undated)[1. Edwards, Eunice. Letter to Mary Edwards at Northampton.]. https://collections.library.yale.edu/catalog/33223558.