@article{NUMA_1974__23_132303,
     author = {K.S. Thomas},
     title = {On the {Approximate} {Solution} of {Operator} {Equations.}},
     journal = {Numerische Mathematik},
     pages = {231--240},
     publisher = {mathdoc},
     volume = {23},
     year = {1974},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/NUMA_1974__23_132303/}
}