1. Amazon Elastic Compute Cloud. http://www.amazon.com/ec2
2. GoGrid. http://www.gogrid.com
3. FlexiScale, http://www.flexiscale.com
4. The SLA@SOI project. http://www.sla-at-soi.eu/
5. R. Perrott, T. Harmer and P. Wright. Provider-independent use of the cloud. In Proceedings of Euro-Par 2009, LNCS, 2009.