@inproceedings{CSL-1999-GradelK,
	author        = "Erich Grädel and Stephan Kreutzer",
	booktitle     = "{Proceedings of the 13th International Workshop on Computer Science Logic / Eighth Annual Conference of the EACSL}",
	doi           = "10.1007/3-540-48168-0_6",
	isbn          = "3-540-66536-6",
	pages         = "67--81",
	publisher     = "{Springer-Verlag}",
	series        = "{Lecture Notes in Computer Science}",
	title         = "{Descriptive Complexity Theory for Constraint Databases}",
	volume        = 1683,
	year          = 1999,
}