M. Karnstedt, K. Sattler, M. Hauswirth, and R. Schmidt. IDEAS '08: Proceedings of the 2008 international symposium on Database engineering &\#38; applications, page 19--28. New York, NY, USA, ACM, (2008)
K. Cheung, H. Frost, M. Marshall, E. Prud'hommeaux, M. Samwald, J. Zhao, and A. Paschke. BMC Bioinformatics, (2009)"We have explored a tool called "FeDeRate", which enables a global SPARQL query to be decomposed into subqueries against the remote databases offering either SPARQL or SQL query interfaces.".
A. Langegger. iiWAS '08: Proceedings of the 10th International Conference on Information Integration and Web-based Applications & Services, page 559--562. New York, NY, USA, ACM, (2008)