title: sideway value algebra for object-relational databases. authors: z. meral özsoyoglu , gultekin özsoyoglu , abdullah al-hamdani , özgür ulusoy , selma ayse özel , ismail sengör altingövde. venue: vldb. year: 2002
title: evaluating functional joins along nested reference sets in object-relational and object-oriented databases. authors: reinhard braumandl , jens clau &#223; en , alfons kemper. venue: very large data bases. year: 1998