Johan Petrini Tore Risch SWARD: Semantic Web Abridged Relational Databases. 455-459 2007 conf/dexaw/2007 DEXA Workshops http://doi.ieeecomputersociety.org/10.1109/DEXA.2007.131 db/conf/dexaw/dexaw2007.html#PetriniR07