1. Balkenius, C., and P. Gärdenfors: “Non-monotonic inferences in neural networks,” in: J.A. Allen, R. Fikes, and E. Sandewall (eds), Principles of Knowledge Representation and Reasoning: Proceedings of the Second International Conference KR'91, (San Mateo, CA: Morgan Kaufmann), (1991) 32–39.
2. Dubois, D., and H. Prade: “Epistemic entrenchment and possibility logic,” in: Artificial Intelligence 50, (1991) 223–239.
3. Freund, M., D. Lehmann and D. Makinson: “Canonical extensions to the infinite case of finitary nonmonotonic inference relations,” in: G. Brewka and H. Freitag (eds), Arbeitspapiere der GMD no. 443: Proceedings of the Workshop on Nonmonotonic Reasoning, (1990) 133–138.
4. Gärdenfors, P.: “On the logic of relevance,” in: Synthese 37, (1978) 351–367.
5. Gärdenfors, P.: Knowledge in Flux: Modeling the Dynamics of Epistemic States. Cambridge, MA: The MIT Press, Bradford Books, 1988.