Thomas Eiter Giovambattista Ianni Thomas Krennwallner Roman Schindlauer Exploiting conjunctive queries in description logic programs. 115-152 2008 53 Ann. Math. Artif. Intell. 1-4 http://dx.doi.org/10.1007/s10472-009-9111-3 db/journals/amai/amai53.html#EiterIKS08