title: join synopses for approximate query answering. authors: swarup acharya , viswanath poosala , phillip b. gibbons , sridhar ramaswamy. venue: sigmod conference. year: 1999
title: aqua : a fast decision support systems using approximate query answers. authors: swarup acharya , phillip b. gibbons , viswanath poosala. venue: very large data bases. year: 1999