@article{journals/jcss/GottlobLS02,
  title = "Hypertree Decompositions and Tractable Queries",
  author = "Georg Gottlob and Nicola Leone and Francesco Scarcello",
  year = "2002",
  journal = "J. Comput. Syst. Sci.",
  number = "3",
  pages = "579-627",
  volume = "64",
  doi = "10.1006/jcss.2001.1809",
}