@article{GDZPPN001182803, title = {Preconditioning Indefinite Discretization Matrices.}, journal = {Numerische Mathematik}, volume = {56}, year = {1989}, pages = {719-734}, zbl = {0663.65042}, url = {http://dml.mathdoc.fr/item/GDZPPN001182803} }
Yserentant, Harry. Preconditioning Indefinite Discretization Matrices.. Numerische Mathematik, Tome 56 (1989) pp. 719-734. http://gdmltest.u-ga.fr/item/GDZPPN001182803/