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, 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.142