Francis Parkman, David Levin (1983). “France and England in North America: Pioneers of France in the New World. The Jesuits of North America in the seventeenth century. La Salle and the discovery of the Great West. The old régime in Canada”, p.27, Library of America
"Philosophy of Science", Volume 37 (p. 157), 1934; later quoted in Roger Gerhard Newton "The Truth of Science: Physical Theories and Reality" (p. 176), 1997.