"A Comprehensive Survey of Multiagent Reinforcement Learning" (2008) by Busoniu et al.: http://dx.doi.org/10.1109/TSMCC.2007.913919
The same authors published a similar article 2 years later, as Luiza Dihoru mentioned above ("Multi-agent Reinforcement Learning: An Overview" : http://link.springer.com/chapter/10.1007%2F978-3-642-14435-6_7)