@inproceedings{Kreutzer00,
  title = "Fixed-point Query Languages for Linear Constraint Databases",
  author = "S. Kreutzer",
  year = "2000",
  booktitle = "Proceedings of the 19th ACM Symp. on Principles of Database Systems (PODS), 2000",
  pages = "116--125",
  publisher = "ACM press",
}