"French Music: From the Death of Berlioz to the Death of Fauré". Book by Martin Cooper (p. 136), 1951; later quoted in "Debussy and Wagner", book by Robin Holloway (p. 207), 1979.
Heraclitus (1981). “The Art and Thought of Heraclitus: A New Arrangement and Translation of the Fragments with Literary and Philosophical Commentary”, p.245, Cambridge University Press
Sir William Osler, Mark E. Silverman, T. J. Murray, Charles S. Bryan, American College of Physicians--American Society of Internal Medicine (2003). “The Quotable Osler”, p.18, ACP Press