Hongwei Zhu 0002 Stuart E. Madnick Michael Siegel Representation and Reasoning About Changing Semantics in Heterogeneous Data Sources. 127-139 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3372&spage=127 2004 conf/semweb/2004swdb SWDB db/conf/semweb/swdb2004.html#ZhuMS04