StephanBloehdorn PhilippCimiano AndreasHotho SteffenStaab An Ontology-based Framework for Text Mining LDV Forum - GLDV Journal for Computational Linguistics and Language Technology 20 87-112 2005 O.Corby R.Dieng C.H\'ebert A conceptual graph model for W3C resource description framework Springer 1867 468–482 2000