Yan Yang Baoliang Liu Zhaogong Zhang Partition Based Hierarchical Index for Text Retrieval. 161-172 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2762&spage=161 2003 conf/waim/2003 WAIM db/conf/waim/waim2003.html#YangLZ03