TY - CONF AU - Speck, René AU - Röder, Michael AU - Oramas, Sergio AU - Espinosa Anke, Luis AU - Ngonga Ngomo, Axel-Cyrille ED - Dragoni, Mauro ED - Solanki, Monika ED - Blomqvist, Eva ID - 26552 T2 - Semantic Web Challenges - 4th SemWebEval Challenge at {ESWC} 2017, Portoroz, Slovenia, May 28 - June 1, 2017, Revised Selected Papers TI - Open Knowledge Extraction Challenge 2017 VL - 769 ER -