Lawrence Cunningham and John Reich, Culture and Values: a survey of the Western Humanities, 5th ed., Vol. 2 (Fort Worth: Harcourt Brace College Publishers, 1998), 97; Fred S. Kleiner and Christin J. Mamiya, Gardner's Art Through the Ages, 12th ed., vol 2 (Belmont, CA: Thomson/Wadsworth, 2005), 624-628; Frederick Hartt, History of Italian Renaissance art: painting, sculpture, architecture 3rd ed. (Englewood Cliffs, N.J.: Prentice-Hall, 1987), 536-548