@article{CIAA-J-2006-SalomaaY07,
	author        = "Kai Salomaa and Sheng Yu",
	doi           = "10.1142/S0129054107004917",
	journal       = "{International Journal of Foundations of Computer Science}",
	number        = 4,
	pages         = "683--698",
	publisher     = "{World Scientific}",
	title         = "{On the State Complexity of Combined Operations and their Estimation}",
	volume        = 18,
	year          = 2007,
}