title: supporting top-k join queries in relational databases. authors: walid g. aref , ahmed k. elmagarmid , ihab f. ilyas. venue: vldb. year: 2003
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