@inproceedings{LICS-2003-LibkinN,
	author        = "Leonid Libkin and Frank Neven",
	booktitle     = "{Proceedings of the 18th IEEE Symposium on Logic in Computer Science}",
	doi           = "10.1109/LICS.2003.1210057",
	isbn          = "0-7695-1884-2",
	pages         = "178--187",
	publisher     = "{IEEE Computer Society}",
	title         = "{Logical Definability and Query Languages over Unranked Trees}",
	year          = 2003,
}