@book{OPUS4-24069,
  title     = {Proceedings of the 26th International Symposium on Theoretical Aspects of Computer Science (STACS'09)},
  editor    = {Susanne Albers and Jean-Yves Marion},
  isbn      = {978-3-939897-09-5},
  url       = {http://www.dagstuhl.de/dagpub/978-3-939897-09-5},
  year      = {2009},
}