Tian-rui Li Ming Qing Jun Ma Yang Xu An Algorithm for Mining Lower Closed Itemsets. 21-24 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3320&spage=21 2004 conf/pdcat/2004 PDCAT db/conf/pdcat/pdcat2004.html#LiQMX04