Claude Debussy's statement of 1910, as quoted in "Debussy on Music" edited and translated by Francoise Lesure and Richard Langham Smith (p. 243), 1977.
"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.