@article{NUMA_1979__33_132654,
     author = {R.B. Kellogg and J. Pitk\"aranta and L. Babuska},
     title = {Direct and {Inverse} {Error} {Estimates} for {Finite} {Elements} {With} {Mesh} {Refinements.}},
     journal = {Numerische Mathematik},
     pages = {447--471},
     publisher = {mathdoc},
     volume = {33},
     year = {1979},
     zbl = {0423.65057},
     url = {http://geodesic.mathdoc.fr/item/NUMA_1979__33_132654/}
}