@inproceedings{AFL-2011-PiaoSV,
	author        = "Xiaoxue Piao and Kai Salomaa and Sándor Vágvölgyi",
	booktitle     = "{Proceedings of the 13th International Conference on Automata and Formal Languages}",
	isbn          = "978-615-5097-19-5",
	pages         = "343--357",
	title         = "{Tree Homomorphisms for Unranked Trees}",
	year          = 2011,
}