@InProceedings{barcelo_et_al:LIPIcs.ICDT.2018.7,
  author =	{Barcel\'{o}, Pablo and Romero, Miguel and Zeume, Thomas},
  title =	{{A More General Theory of Static Approximations for Conjunctive Queries}},
  booktitle =	{21st International Conference on Database Theory (ICDT 2018)},
  pages =	{7:1--7:22},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-063-7},
  ISSN =	{1868-8969},
  year =	{2018},
  volume =	{98},
  editor =	{Kimelfeld, Benny and Amsterdamer, Yael},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ICDT.2018.7},
  URN =		{urn:nbn:de:0030-drops-86021},
  doi =		{10.4230/LIPIcs.ICDT.2018.7},
  annote =	{Keywords: conjunctive queries, hypertreewidth, approximations, pebble games}
}