Minh Dao-Tran Thomas Eiter Michael Fink Thomas Krennwallner Modular Nonmonotonic Logic Programming Revisited. 145-159 2009 ICLP http://dx.doi.org/10.1007/978-3-642-02846-5_16 conf/iclp/2009 db/conf/iclp/iclp2009.html#Dao-TranEFK09