@article{NUMA_1990__57_6-7_133431,
     author = {Zbigniew Leyk},
     title = {Galerkin {Method} and {Optimal} {Error} {Algorithms} in {Hilbert} {Spaces.}},
     journal = {Numerische Mathematik},
     pages = {1--14},
     publisher = {mathdoc},
     volume = {57},
     number = {6-7},
     year = {1990},
     zbl = {0672.65030},
     url = {http://geodesic.mathdoc.fr/item/NUMA_1990__57_6-7_133431/}
}