Narain H. Gehani H. V. Jagadish Active Database Facilities in Ode. 19-22 1992 http://sites.computer.org/debull/92DEC-CD.pdf 15 IEEE Data Eng. Bull. 1-4 db/journals/debu/debu15.html#GehaniJ92 conf/vldb/GehaniJ91 conf/sigmod/GehaniJS92 conf/vldb/GehaniJS92 conf/vldb/JagadishQ92 conf/oodbs/JagadishS92