title: the aqua approximate query answering system. authors: sridhar ramaswamy , swarup acharya , phillip b. gibbons , viswanath poosala. venue: sigmod conference. year: 1999
title: approximate query processing using wavelets. authors: kaushik chakrabarti , minos n. garofalakis , rajeev rastogi , kyuseok shim. venue: very large data bases. year: 2000