@inproceedings{GraedelKre99,
  title = "Descriptive Complexity Theory for Constraint Databases",
  author = "E. Gr{\"a}del and S. Kreutzer",
  year = "1999",
  booktitle = "Computer Science Logic (CSL)",
  number = "1683",
  pages = "67 -- 82",
  publisher = "Springer",
  series = "LNCS",
}