title: vxmlr : a visual xml-relational database system. authors: aoying zhou , wenyun ji , shihui zheng , hongjun lu , yuqi liang , zengping tian , long zhang. venue: vldb. year: 2001
title: sap r/3 ( tutorial ) : a database application system. authors: alfons kemper , donald kossmann , florian matthes. venue: international conference on management of data. year: 1998