@inproceedings{Kreutzer01,
  title = "Query Languages for Constraint Databases: First-Order Logic, Fixed-Points, and Convex Hulls",
  author = "S. Kreutzer",
  year = "2001",
  booktitle = "Proceedings of the 8th International Conference on Database Theory (ICDT)",
  number = "1973",
  pages = "248--262",
  publisher = "Springer",
  series = "#lncs#",
}