Database Theory - ICDT 2003 9th International Conference, Siena, Italy, January 8-10, 2003, Proceedings - Calvanese, Diego; Calvanese, Diego; Lenzerini, Maurizio; Lenzerini, Maurizio; Motwani, Rajeev; Motwani, Rajeev (Springer Berlin Heidelberg : Imprint: Springer, 2003)