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2. Aristotle: 1952, Politica, The Works of Aristotle, vol. X, translated into English under the Editorship of W.D. Ross, Clarendon Press, Oxford. Reprint from sheets of the First Edition 1921.
3. Buchanan, J.M. and Tullock, G.: 1962, The Calculas of Consent. Logical Foundations of Constitutional Democracy, University of Michigan Press, Ann Arbor, Michigan.
4. Cicero: 1923 (Reprint 1971), De Divinatione, trans. W.A. Falconer, Cicero in Twenty-eight Volumes, vol. XX, Loeb Classical Library, Harvard University Press, Cambridge.
5. Engelhardt, H.T., Jr.: 1986, The Foundations of Bioethics, Oxford University Press, New York, Oxford.