1. Expressing opposition in the object model, first step towards negation
2. Aristotle. Categories. In Ross {28}. Translated by E.M. Edghill. Also available from The Internet Classics Archive (http://classics.mit.edu).]] Aristotle. Categories. In Ross {28}. Translated by E.M. Edghill. Also available from The Internet Classics Archive (http://classics.mit.edu).]]
3. Aristotle. On Interpretation. In Ross {28}. Translated by E.M. Edghill. Also available from The Internet Classics Archive (http://classics.mit.edu).]] Aristotle. On Interpretation. In Ross {28}. Translated by E.M. Edghill. Also available from The Internet Classics Archive (http://classics.mit.edu).]]
4. Aristotle. Prior Analytics. In Ross {28}.]] Aristotle. Prior Analytics. In Ross {28}.]]