@inproceedings{PODS-2013-Wijsen,
	author        = "Jef Wijsen",
	booktitle     = "{Proceedings of the 32nd Symposium on Principles of Database Systems}",
	doi           = "10.1145/2463664.2463666",
	isbn          = "978-1-4503-2066-5",
	pages         = "189--200",
	publisher     = "{ACM}",
	title         = "{Charting the tractability frontier of certain conjunctive query answering}",
	year          = 2013,
}