MLA

Edwards, Jonathan, 1703-1758. Essay on the Trinity. Box 21, folder 1255. n.d.. https://collections.library.yale.edu/catalog/10690873.

APA, 6th edition

Edwards, Jonathan, 1703-1758. (["Box 21, folder 1255"])(n.d.)[Essay on the Trinity]. https://collections.library.yale.edu/catalog/10690873.