Tadeusz Pankowski Jolanta Cybulka Adam Meissner Reasoning About XML Schema Mappings in the Presence of Key Constraints and Value Dependencies. 374-376 2007 conf/rr/2007 RR http://dx.doi.org/10.1007/978-3-540-72982-2_35 db/conf/rr/rr2007.html#PankowskiCM07