On the Complexity of Model Checking for Propositional Default Logics: New Results and Tractable Cases.

Robert Baumgartner Georg Gottlob On the Complexity of Model Checking for Propositional Default Logics: New Results and Tractable Cases. 64-69 1999 conf/ijcai/99 IJCAI db/conf/ijcai/ijcai99.html#BaumgartnerG99