Sunita Sarawagi Vinay S. Deshpande Sourabh Kasliwal Efficient top-k count queries over imprecise duplicates. 450-461 2009 EDBT http://doi.acm.org/10.1145/1516360.1516413 conf/edbt/2009 db/conf/edbt/edbt2009.html#SarawagiDK09