Witold Lukaszewicz Ewa Madalinska-Bugaj Lazy Knowledge Base Update. 61-70 2001 conf/ieaaie/2001 IEA/AIE http://link.springer.de/link/service/series/0558/bibs/2070/20700061.htm db/conf/ieaaie/ieaaie2001.html#LukaszewiczM01