@inproceedings{ferrante2007-1,
	author="A. Ferrante and M. Pavon and F. Ramponi",
	title="Constrained approximation in the Hellinger distance",
	booktitle="Proceedings of the European Control Conference 2007 (ecc07)",
	year="2007",
	month=" Luglio",
	pages="322-327",
	location="Kos Grecia"
}