Luís Moniz Pereira, Alexandre Miguel Pinto. Approved Models for Normal Logic Programs. In Nachum Dershowitz, Andrei Voronkov, editors, Logic for Programming, Artificial Intelligence, and Reasoning, 14th International Conference, LPAR 2007, Yerevan, Armenia, October 15-19, 2007, Proceedings. Volume 4790 of Lecture Notes in Computer Science, pages 454-468, Springer, 2007. [doi]