Cèsar Fernández, Hector Geffner, Felip Manyà: Artificial Intelligence Research and Development - Proceedings of the 14th International Conference of the Catalan Association for Artificial Intelligence, Lleida, Catalonia, Spain, October 26-28, 2011. Frontiers in Artificial Intelligence and Applications 232, IOS Press 2011, ISBN 978-1-60750-841-0