Kai-Uwe Sattler Oliver Dunemann Ingolf Geist Gunter Saake Stefan Conrad Limiting Result Cardinalities for Multidatabase Queries Using Histograms. 152-167 2001 conf/bncod/2001 BNCOD http://link.springer.de/link/service/series/0558/bibs/2097/20970152.htm db/conf/bncod/bncod2001.html#SattlerDGSC01