E. Kitzelmann. ECAI 2008, 18th European Conference on Artificial Intelligence, Proceedings, volume 178 of Frontiers in Artificial Intelligence and Applications, page 781--782. Amsterdam, Netherlands, IOS Press, (2008)
E. Kitzelmann. 18th International Symposium on Logic-Based Program Synthesis and Transformation, Revised Selected Papers, volume 5438 of LNCS, page 87--102. Springer-Verlag, (2009)