1. C. E. Alchourrón and D.Makinson. Hierarchies of regulations and their logic. In New Studies in Deontic Logic, R.Hilpinened., pp. 125--148. Springer, 1981.
2. L. Amgoud and S. Vesic. Handling inconsistency with preference-based argumentation. InScalable Uncertainty Management—4th International Conference, SUM 2010, Toulouse, France, September 27–29, 2010. Proceedings, Lecture Notes in Computer Science, A.Deshpande and A.Hunter, eds, 6379, pp. 56--69. Springer, 2010.
3. Permissions and obligations in hierarchical normative systems.;Boella;Proceedings of the 9th International Conference on Artificial Intelligence and Law, ICAIL 2003 Edinburgh, Scotland, UK, June 24–28, 2003,2003
4. G. Boella , L. W. N.van der Torre and H.Verhagen. Ten challenges for normative multiagent systems. In Programming Multi-Agent Systems, 31.08. - 05.09.2008, Dagstuhl, 2008.
5. G. Brewka . Preferred subtheories: An extended logical framework for default reasoning. In Proceedings of the 11th International Joint Conference on Artificial Intelligence. Detroit, MI, USA, August 1989, N. S.Sridharaned., pp. 1043--1048. AAAI, 1989.