title: unisql 's next-generation object-relational database management system. authors: phil janus , albert d'andrea. venue: sigmod record. year: 1996
title: a general technique for querying xml documents using a relational database system. authors: jayavel shanmugasundaram , eugene shekita , jerry kiernan , rajasekar krishnamurthy , efstratios viglas , jeffrey naughton , igor tatarinov. venue: acm sigmod record. year: 2001