@BOOK {
	EDITOR = "Pablo Barcel{\'o} and Marco Calautti",
	TITLE = "Proceedings of the 22nd International Conference on Database Theory (ICDT)",
	MONTH = "Mar",
	YEAR = "2019",
	ADDRESS = "Lisbon, Portugal",
	PUBLISHER = "ACM Press",
	SERIES ="ACM International Conference Proceeding Series",
	}