MLA
Wesley, Charles, D.D., 1793-1859. Letter from Charles Wesley D.D. to Charles Wesley, [London] (Manuscript copy, original given to G[eorge] J[ohn] Stephenson) - May 3, 1823. May 3, 1823. Wesleyana Collection. Pitts Theology Library. https://digital.library.emory.edu/purl/423612jms7-cor.
APA, 6th edition
Wesley, Charles, D.D., 1793-1859. (May 3, 1823)[Letter from Charles Wesley D.D. to Charles Wesley, [London] (Manuscript copy, original given to G[eorge] J[ohn] Stephenson) - May 3, 1823]. Wesleyana Collection, Pitts Theology Library. https://digital.library.emory.edu/purl/423612jms7-cor.
Chicago
Wesley, Charles, D.D., 1793-1859, Letter from Charles Wesley D.D. to Charles Wesley, [London] (Manuscript copy, original given to G[eorge] J[ohn] Stephenson) - May 3, 1823, May 3, 1823, Wesleyana Collection, Pitts Theology Library. https://digital.library.emory.edu/purl/423612jms7-cor.