M. Bienvenu, T. Eiter, C. Lutz, M. Ortiz de la Fuente, M. Simkus:
"Query Answering in the Description Logic S";
Report for TU Wien, Institut fuer Informationssysteme, INFSYS RR-1843-10-01; Report No. INFSYS RR 1843-10-01, 2010; 18 pages.
http://www.kr.tuwien.ac.at/research/reports/rr1001.pdf