@inbook {700,
	title = {Stable estimates in equation-error identification: an open problem},
	booktitle = {Open Problems in Mathematical Systems and Control Theory},
	year = {1999},
	publisher = {Springer-Verlag},
	organization = {Springer-Verlag},
	chapter = {28},
	isbn = { 1-85233-044-9},
	url = {http://perso.uclouvain.be/vincent.blondel/books/openprobs/},
	author = {R. L{\'o}pez-Valcarce and S. Dasgupta}
}
