Constantinos Daskalakis Grant Schoenebeck Gregory Valiant Paul Valiant On the complexity of Nash equilibria of action-graph games. 710-719 2009 SODA http://doi.acm.org/10.1145/1496770.1496848 conf/soda/2009 db/conf/soda/soda2009.html#DaskalakisSVV09