@inproceedings{PODS-2004-FaginPKT,
	author        = "Ronald Fagin and Phokion G. Kolaitis and Lucian Popa and Wang Chiew Tan",
	booktitle     = "{Proceedings of the 23rd Symposium on Principles of Database Systems}",
	doi           = "10.1145/1055558.1055572",
	ee            = "http://www.acm.org/sigmod/pods/proc04/pdf/P-09.pdf",
	isbn          = "1-58113-858-X",
	pages         = "83--94",
	publisher     = "{ACM}",
	title         = "{Composing Schema Mappings: Second-Order Dependencies to the Rescue}",
	year          = 2004,
}