@string{ESA09 = {European Symposium, Copenhagen}}

@inproceedings{CKS09,
  author    = {G. Christodoulou and
               E. Koutsoupias and
               P. Spirakis},
  title     = {On the Performance of Approximate Equilibria in Congestion
               Games},
  booktitle = ESA09,
  year      = {2009},
  month	    = {7-9} # sep,
  address   = {Copenhagen, Denmark},
  pages     = {251-262},
  ee        = {http://dx.doi.org/10.1007/978-3-642-04128-0_22},
  note	    = {Also in arXiv:cs/0804.3160}
}