Thomas Sully. Thomas Sully, Philadelphia, Pa. to George Catlin, 1839 July 16. George Catlin papers, undated. Archives of American Art, Smithsonian Institution.
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.