1. Outerjoins as disjunctions;Galindo-Legaria,1994
2. Integrating information by outerjoins and full disjunctions;Rajaraman,1996
3. Computing full disjunctions;Kanza,2003
4. Optimal aggregation algorithms for middleware;Fagin,2001
5. Evaluating top-k queries over web-accessible databases;Marian;ACM Trans. Database Systems,2004