George Berkeley, Alexander Campbell Fraser (1732). “The Works of George Berkeley, D.D., Formerly Bishop of Cloyne: Philosophical works, 1732-33: Alciphron. The theory of vision”, p.32
George Berkeley (1752). “Alciphron: Or, The Minute Philosopher. In Seven Dialogues Containing an Apology for the Christian Religion Against Those who are Called Free-thinkers”, p.112