Mohamed Chachoua Daniel Pacholczyk Qualitative Reasoning Under Ignorance and Information-Relevant Extraction. 483-506 2002 4 Knowl. Inf. Syst. 4 http://link.springer.de/link/service/journals/10115/bibs/2004004/20040483.htm db/journals/kais/kais4.html#ChachouaP02