Thomas Sully. Thomas Sully, Philadelphia, Pa. letter to Asher Brown Durand, New York, N.Y., 1825 March 21. Charles Henry Hart autograph collection, 1731-1918. Archives of American Art, Smithsonian Institution.
Thomas Sully. Thomas Sully, Philadelphia, Pa. to George Catlin, 1839 July 16. George Catlin papers, undated. Archives of American Art, Smithsonian Institution.