@inproceedings{STOC-1979-ChandraH,
	author        = "Ashok K. Chandra and David Harel",
	booktitle     = "{Proceedings of the 11th Annual ACM Symposium on Theory of Computing}",
	doi           = "10.1145/800135.804423",
	pages         = "309--318",
	publisher     = "{ACM}",
	title         = "{Computable Queries for Relational Data Bases}",
	year          = 1979,
}