1. Addison Joseph, The Spectator, Vol. 5, ed. Alexander Chalmers, D. Appleton, New York 1879.
2. Avison Charles, An Essay on Musical Expression, 3rd ed., Lockyer Davis, London 1775.
3. Ayer Alfred Jules, The Problem of Knowledge, Penguin Books, Harmondsworth 1961.
4. Beattie James, The Philosophical and Critical Works, Vol. 1, Georg Olms, Hildesheim-New York 1975.
5. Bell Clive, Art, Capricorn Books, New York 1958.