Semantics in Databases Second International Workshop, Dagstuhl Castle, Germany, January 7-12, 2001, Revised Papers - Bertossi, Leopoldo; Bertossi, Leopoldo; Katona, Gyula O.H; Katona, Gyula O.H; Schewe, Klaus-Dieter; Schewe, Klaus-Dieter; Thalheim, Bernhard; Thalheim, Bernhard (Springer Berlin Heidelberg : Imprint: Springer, 2003)