Sebastian Hellmann Jens Lehmann Sören Auer Learning of OWL Class Descriptions on Very Large Knowledge Bases. 2008 International Semantic Web Conference (Posters & Demos) http://ceur-ws.org/Vol-401/iswc2008pd_submission_83.pdf conf/semweb/2008p db/conf/semweb/iswc2008p.html#HellmannLA08