"The Philosophical Works: Treatise On Tolerance, Philosophical Dictionary, Candide, Letters on England, Plato’s Dream, Dialogues, The Study of Nature, Ancient Faith and Fable, Zadig…".
Letter to Pierre-Joseph Luneau de Boisjermain on October 21, 1769. "Oeuvres Complètes de Voltaire: Correspondance". Book published by Garnier frères, Paris, Volume XIV, letter #7692, p. 478, 1882.