William Shakespeare (1838). “The Pictorial edition of the works of Shakspere, ed. by C. Knight. [8 vols., including a vol. entitled William Shakspere, by C. Knight].”
George Santayana, Marianne S. Wokeck, Martin A. Coleman, James Gouinlock (2015). “The Life of Reason Or The Phases of Human Progress: Reason in Art, Volume VII, Book Four”, p.65, MIT Press
Galileo Galilei, Andrea Frova, Mariapiera Marenzana (2006). “Thus Spoke Galileo: The Great Scientist's Ideas and Their Relevance to the Present Day”, p.174, Oxford University Press