MLA
Wesley, Sarah, 1759-1828. Letter from Sarah Wesley to [Probyn], London - [written between August 19, 1800 to August 19, 1819]. August 1800 to August 1819. Wesleyana Collection. Pitts Theology Library. https://digital.library.emory.edu/purl/197xksn0n0-cor.
APA, 6th edition
Wesley, Sarah, 1759-1828. (August 1800 to August 1819)[Letter from Sarah Wesley to [Probyn], London - [written between August 19, 1800 to August 19, 1819]]. Wesleyana Collection, Pitts Theology Library. https://digital.library.emory.edu/purl/197xksn0n0-cor.
Chicago
Wesley, Sarah, 1759-1828, Letter from Sarah Wesley to [Probyn], London - [written between August 19, 1800 to August 19, 1819], August 1800 to August 1819, Wesleyana Collection, Pitts Theology Library. https://digital.library.emory.edu/purl/197xksn0n0-cor.