@inproceedings{STOC-1989-AfratiC,
	author        = "Foto N. Afrati and Stavros S. Cosmadakis",
	booktitle     = "{Proceedings of the 21st Annual ACM Symposium on Theory of Computing}",
	doi           = "10.1145/73007.73018",
	isbn          = "0-89791-307-8",
	pages         = "113--126",
	publisher     = "{ACM}",
	title         = "{Expressiveness of Restricted Recursive Queries}",
	year          = 1989,
}