Sungyoung Kim Soyoun Park Minhwan Kim Central Object Extraction for Object-Based Retrieval. 39-49 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2728&spage=39 2003 conf/civr/2003 CIVR db/conf/civr/civr2003.html#KimPK03