Foto N. Afrati Matthew Damigos Manolis Gergatsoulis On Solving Efficiently the View Selection Problem under Bag-semantics. 2008 BIRTE (Informal Proceedings) http://www.vldb.org/conf/2008/workshops/WProc_BIRTE/p4-afrati.pdf conf/birte/2008 db/conf/birte/birte2008.html#AfratiDG08