title: report on ngits ' 99 : the 4th international workshop on next generation information technologies and systems. authors: opher etzion. venue: sigmod record. year: 1999
title: report on the 5th international workshop on knowledge representation meets databases ( krdb ' 98 ). authors: alex borgida , vinay k. chaudhri , martin staudt. venue: acm sigmod record. year: 1998