title: optimizing queries with universal quantification in object-oriented and object-relational databases guido moerkotte , jens claußen , klaus peithner , alfons kemper vldb 1997. authors: nan. venue: nan. year: nan
title: accessing a relational database through an object-oriented database interface jack a. orenstein , d. n. kamber 1995. authors: nan. venue: very large data bases. year: nan