Nassau William Senior, Harriet Elizabeth Beecher Stowe, Charles Sumner (1856). “American slavery: repr. of an article [by N.W. Senior, entitled Slavery in the United States] on 'Uncle Tom's cabin' [by H.E.B. Stowe] and of mr. Sumner's speech of the 19th and 20th of May, 1856. With a notice of the events which followed that speech”, p.143