Arturo Crespo Orkut Buyukkokten Hector Garcia-Molina Query Merging: Improving Query Subscription Processing in a Multicast Environment. 174-191 2003 15 IEEE Trans. Knowl. Data Eng. 1 http://computer.org/tkde/tk2003/k0174abs.htm db/journals/tkde/tkde15.html#CrespoBG03