title: olap , relational , and multidimensional database systems. authors: george colliat. venue: sigmod record. year: 1996
title: storing and querying ordered xml using a relational database system. authors: igor tatarinov , stratis d. viglas , kevin beyer , jayavel shanmugasundaram , eugene shekita , chun zhang. venue: international conference on management of data. year: 2002