@article {Nicola-et-al-2011,
	title = {A general extending and constraining procedure for linear iterative methods},
	journal = {Int.~J.~Comp.~Math.},
	year = {2011},
	note = {in press},
	url = {http://dx.doi.org/10.1080/00207160.2011.634002},
	author = {Nicola, A. and Stefania Petra and Popa, C. and Christoph Schn{\"o}rr}
}
