Diego Calvanese Giuseppe De Giacomo Domenico Lembo Maurizio Lenzerini Riccardo Rosati Data Complexity of Query Answering in Description Logics. 2005 conf/dlog/2005 Description Logics http://www.ceur-ws.org/Vol-147/19-CalvaneseEtAl.pdf db/conf/dlog/dlog2005.html#CalvaneseGLLR05