Marios Hadjieleftheriou Xiaohui Yu Nick Koudas Divesh Srivastava Hashed samples: selectivity estimators for set similarity selection queries. 201-212 2008 1 PVLDB 1 http://www.vldb.org/pvldb/1/1453883.pdf db/journals/pvldb/pvldb1.html#HadjieleftheriouYKS08