Henry Morton Stanley (1873). “How I Found Livingstone: Travels, Adventures, and Discoveries in Central Africa; Including Four Months' Residence with Dr. Livingstone”, p.12
John Henninger Reagan's speech (January 15, 1861), as quoted in the Congressional Globe, 36th Congress, 2nd Session (p. 391); also quoted in Kenneth M. Stampp "The Causes of the Civil War" (p. 89), 1959.