MLA

Backus, Isaac, 1724-1806. All true ministers of the gospel are called into that work by the special influences of the holy spirit. Box 3, folder 1. 1754. https://collections.library.yale.edu/catalog/33530506.

APA, 6th edition

Backus, Isaac, 1724-1806. (["Box 3, folder 1"])(1754)[All true ministers of the gospel are called into that work by the special influences of the holy spirit]. https://collections.library.yale.edu/catalog/33530506.