Hector Garcia-Molina Yannis Papakonstantinou Dallan Quass Anand Rajaraman Yehoshua Sagiv Jeffrey D. Ullman Vasilis Vassalos Jennifer Widom The TSIMMIS Approach to Mediation: Data Models and Languages. 117-132 1997 8 J. Intell. Inf. Syst. 2 db/journals/jiis/jiis8.html#Garcia-MolinaPQRSUVW97