Hongsik Rho Wen-Chi Hou Dunren Che Chih-Fang Wang Querying Semistructured Data Efficiently. 18-27 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2736&spage=18 2003 conf/dexa/2003 DEXA db/conf/dexa/dexa2003.html#RhoHCW03