@article{GDZPPN001183710, title = {Galerkin Method and Optimal Error Algorithms in Hilbert Spaces.}, journal = {Numerische Mathematik}, volume = {58}, year = {1990}, pages = {1-14}, zbl = {0672.65030}, url = {http://dml.mathdoc.fr/item/GDZPPN001183710} }
Leyk, Zbigniew. Galerkin Method and Optimal Error Algorithms in Hilbert Spaces.. Numerische Mathematik, Tome 58 (1990) pp. 1-14. http://gdmltest.u-ga.fr/item/GDZPPN001183710/