@article{journals/corr/abs-cs-0602004,
  title = "Conjunctive Queries over Trees",
  author = "Georg Gottlob and Christoph Koch and Klaus U. Schulz",
  year = "2006",
  journal = "{CoRR}",
  url = "http://arxiv.org/abs/cs/0602004",
  volume = "abs/cs/0602004",
}