Roberto Sebastiani Michele Vescovi Axiom Pinpointing in Lightweight Description Logics via Horn-SAT Encoding and Conflict Analysis. 84-99 2009 CADE http://dx.doi.org/10.1007/978-3-642-02959-2_6 conf/cade/2009 db/conf/cade/cade2009.html#SebastianiV09