Marcelino C. Pequeno Rodrigo de M. S. Veras Wladimir A. Tavares Handling Exceptions in nonmonotonic reasoning. 2007 conf/lanmr/2007 LA-NMR http://www.ceur-ws.org/Vol-286/LANMR07_04.pdf db/conf/lanmr/lanmr2007.html#PequenoVT07