http://doi.acm.org/10.1145/333607.333610 db/journals/sigmod/BoulosO99.html Jihad Boulos Kinji Ono Cost Estimation of User-Defined Methods in Object-Relational Database Systems. 22-28 sigmodR/28-3/P022.pdf 1999 28 SIGMOD Record 3 http://www.acm.org/sigmod/record/issues/9909/boulos.pdf db/journals/sigmod/sigmod28.html#BoulosO99 ... conf/vldb/ChaudhuriS96 conf/sigmod/HellersteinS93 conf/sigmod/Hellerstein94 conf/sigmod/PoosalaIHS96 conf/vldb/ShivakumarGC98