1. Alchourrón, C. (1993). Philosophical foundations of deontic logic and the logic of defeasible conditionals. In J.-J. C. Meyer & R. J. Wieringa (Eds.), Deontic logic in computer science (pp. 43–84). Chichester: John Wiley & Sons.
2. Aristotle. (1928). Prior analytics (A. J. Jenkinson, Trans.). In W. D. Ross (Ed.), The works of Aristotle (Vol. 1). London: Oxford University Press.
3. Aristotle. (1942). The Nicomachean ethics (W. D. Ross, Trans.). London: Oxford University Press.
4. Berlin, I. (1969). Four essays on liberty. Oxford: Oxford University Press.
5. Bobzien, S. (2002). The development of modus ponens in antiquity: From Aristotle to the 2nd century AD. Phronesis, 47, 359–394.