1. Abiteboul S. and Duschka O.M. Complexity of answering queries using materialized views. In Proc. 17th ACM SIGACT-SIGMOD-SIGART Symp. on Principles of Database Systems, 1998, pp. 254–263.
2. Carey M.J., Haas L.M., Schwarz P.M., Arya M., Cody W.F., Fagin R., Flickner M., Luniewski A., Niblack W., Petkovic D., Thomas II J., Williams J.H., and Wimmers E.L. Towards heterogeneous multimedia information systems: The Garlic approach. In Proc. 5th Int. Workshop on Research Issues on Data Eng., 1995, pp. 124–131.
3. Fagin R., Kolaitis P.G., Miller R.J., and Popa L. Data exchange: Semantics and query answering. In Proc. Int. Conf. on Database Theory, 2002. pp. 207–224.
4. Friedman M., Levy A., and Millstein T. Navigational plans for data integration. In Proc. 16th National Conf. on AI and 11th Innovative Applications of AI Conf., 1999.
5. Garcia-Molina H.K., Papakonstantinou Y.K., Quass D.K., Rajaraman A.K., Sagiv Y.K., Ullman J.K., Vassalos V.K., and Widom J.K. The TSIMMIS approach to mediation: data models and languages. J. Intell. Inf. Syst., 8(2):117–132, 1997.