Thomas Eiter Carsten Lutz Magdalena Ortiz Mantas Simkus Query Answering in Description Logics: The Knots Approach. 26-36 2009 WoLLIC http://dx.doi.org/10.1007/978-3-642-02261-6_3 conf/wollic/2009 db/conf/wollic/wollic2009.html#EiterLOS09