@article{CKS11,
  title = "On the Performance of Approximate Equilibria in Congestion Games",
  author = "George Christodoulou and Elias Koutsoupias and Paul G. Spirakis",
  year = "2011",
  journal = "Algorithmica",
  number = "1",
  pages = "116-140",
  volume = "61",
}