title: java and relational databases : sqlj ( tutorial ). authors: johannes klein , richard pledereder , gray clossman , brian becker , phil shaw , mark hapner. venue: sigmod conference. year: 1998
title: object-relational database systems ( tutorial ) : principles , products and challenges. authors: michael j. carey , nelson m. mattos , anil k. nori. venue: international conference on management of data. year: 1997