title: implementation of two semantic query optimization techniques in db2 universal database. authors: k. bernhard schiefer , fred koo , t. y. cliff leung , linqi liu , jarek gryz , xiaoyan qian , qi cheng. venue: vldb. year: 1999
title: semantic assumptions and query evaluation in temporal databases. authors: claudio bettini , x. sean wang , elisa bertino , sushil jajodia. venue: international conference on management of data. year: 1995