Graham Cormode Antonios Deligiannakis Minos N. Garofalakis Andrew McGregor Probabilistic Histograms for Probabilistic Data. 526-537 2009 2 PVLDB 1 http://www.vldb.org/pvldb/2/vldb09-394.pdf db/journals/pvldb/pvldb2.html#CormodeDGM09