MLA

Backus, Isaac, 1724-1806. A discourse concerning the materials, the manner of building, and power of organizing of the church of Christ. Box 3, folder 4. 1773. https://collections.library.yale.edu/catalog/33530554.

APA, 6th edition

Backus, Isaac, 1724-1806. (["Box 3, folder 4"])(1773)[A discourse concerning the materials, the manner of building, and power of organizing of the church of Christ]. https://collections.library.yale.edu/catalog/33530554.