Georgios N. Yannakakis John Levine John Hallam Emerging Cooperation With Minimal Effort: Rewarding Over Mimicking. 382-396 2007 11 IEEE Trans. Evolutionary Computation 3 http://dx.doi.org/10.1109/TEVC.2006.882429 db/journals/tec/tec11.html#YannakakisLH07