A.  Nicola, Petra, S., Popa, C., and Schnörr, C., ?A general extending and constraining procedure for linear iterative methods?, Int.~J.~Comp.~Math., 2011.

A.  Nicola, Petra, S., Popa, C., and Schnörr, C., ?A general extending and constraining procedure for linear iterative methods?, Int. J. Comp. Math., 2011.

A.  Nicola, Petra, S., Popa, C., and Schnörr, C., ?On a general extending and constraining procedure for linear iterative methods?, IWR, University of Heidelberg, 2009.

A.  Nicola, Petra, S., Popa, C., and Schnörr, C., ?On a general extending and constraining procedure for linear iterative methods?, IWR, University of Heidelberg, 2009.