title: a system for watermarking relational databases. authors: peter j. haas , rakesh agrawal , jerry kiernan. venue: sigmod conference. year: 2003
title: vxmlr : a visual xml-relational database system. authors: aoying zhou , hongjun lu , shihui zheng , yuqi liang , long zhang , wenyun ji , zengping tian. venue: very large data bases. year: 2001