1. Abercrombie, M. L. J.: 1974, The Anatomy of Judgment, Penguin Books, London.
2. Adler, M. J.: 1927, Dialectic, Harcourt, Brace & Co., New York, p. 243, 247.
3. Aquinas, T., Summa Theologiae, transl. by W. P. Hughes, Leonine text, la 2ae, Question 57, art, 3–4.
4. Aristotle: 1940, Metaphysics, transl. by W. D. Ross, The Clarendon Press, Oxford.
5. Bernard, C.: 1927, An Introduction to the Study of. Experimental Medicine, Macmillan, New York, p. 203.