Ewa Madalinska-Bugaj Witold Lukaszewicz Formalizing Defeasible Logic in CAKE. 193-213 2003 57 Fundam. Inform. 2-4 http://iospress.metapress.com/openurl.asp?genre=article&issn=0169-2968&volume=57&issue=2&spage=193 db/journals/fuin/fuin57.html#Madalinska-BugajL03