@misc{GaulGutknechtLiesenetal.2011, author = {Andr{\´e} Gaul and Martin H. Gutknecht and J{\"o}rg Liesen and Reinhard Nabben}, title = {Deflated and augmented Krylov subspace methods: Basic Facts and a Breakdown-free deflated MINRES}, type = {preprintmatheon}, year = {2011}, }