Henrik Legind Larsen, Gabriella Pasi, Daniel Ortiz Arroyo, Troels Andreasen, Henning Christiansen: Flexible Query Answering Systems, 7th International Conference, FQAS 2006, Milan, Italy, June 7-10, 2006, Proceedings. Lecture Notes in Computer Science 4027, Springer 2006, ISBN 3-540-34638-4