@article{NUMA_1992__61_3_133607,
     author = {Giles Auchmuty},
     title = {A posteriori error estimates for linear equations.},
     journal = {Numerische Mathematik},
     pages = {1--6},
     year = {1992},
     volume = {61},
     number = {3},
     zbl = {0747.65027},
     url = {http://geodesic.mathdoc.fr/item/NUMA_1992__61_3_133607/}
}