Dimitris Kotzinos Sofia Pediaditaki Apostolos Apostolidis Nikolaos Athanasis Vassilis Christophides Online curriculum on the semantic Web: the CSD-UoC portal for peer-to-peer e-learning. 307-314 2005 conf/www/2005 WWW http://doi.acm.org/10.1145/1060745.1060792 db/conf/www/www2005.html#KotzinosPAAC05