Zhimao Guo Zhengchuan Xu Shuigeng Zhou Aoying Zhou Ming Li Index Selection for Efficient XML Path Expression Processing. 261-272 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2814&spage=261 2003 conf/er/2003w ER (Workshops) db/conf/er/erw2003.html#GuoXZZL03