Henri Poincare Quotes about Nature
Henri Poincare (2012). “The Value of Science: Essential Writings of Henri Poincare”, p.318, Modern Library
"Science and Method". Book by Henri Poincaré, translated by Francis Maitland. Part I, Chapter 1: "The Selection of Facts", p. 22, 1914.
"Henri Poincaré, Critic of Crisis: Reflections on His Universe of Discourse". Book by Tobias Dantzig, p. 8, 1954.