Thomas Eiter Carsten Lutz Magdalena Ortiz Mantas Simkus Query Answering in Description Logics with Transitive Roles. 759-764 2009 IJCAI http://ijcai.org/papers09/Papers/IJCAI09-131.pdf conf/ijcai/2009 db/conf/ijcai/ijcai2009.html#EiterLOS09