@article{ETNA_1999__8__a0,
     author = {Gradinaru,  V. and Hiptmair,  R.},
     title = {Whitney elements on pyramids},
     journal = {Electronic transactions on numerical analysis},
     pages = {154--168},
     year = {1999},
     volume = {8},
     zbl = {0970.65120},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ETNA_1999__8__a0/}
}