title: the mlpq/gis constraint database system. authors: yuguo liu , yiming li , pradip kanjamala , rui chen , yonghui wang , peter z. revesz. venue: sigmod conference. year: 2000
title: temporal conditions and integrity constraints in active database systems. authors: a. prasad sistla , ouri wolfson. venue: international conference on management of data. year: 1995