@article{CMUC_1970__11_3_a10,
     author = {Babu\v{s}ka, Ivo},
     title = {Computation of derivatives in the finite element method},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {545--558},
     publisher = {mathdoc},
     volume = {11},
     number = {3},
     year = {1970},
     mrnumber = {0275694},
     zbl = {0219.65089},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1970__11_3_a10/}
}