@article{GDZPPN001176676,
title = {On Finite Element Approximation of the Gradient for Solution of Poisson Equation.},
journal = {Numerische Mathematik},
volume = {37},
year = {1981},
pages = {333-338},
zbl = {0463.65073},
url = {http://dml.mathdoc.fr/item/GDZPPN001176676}
}
Neittaanmäki, P.; Saranen, J. On Finite Element Approximation of the Gradient for Solution of Poisson Equation.. Numerische Mathematik, Tome 37 (1981) pp. 333-338. http://gdmltest.u-ga.fr/item/GDZPPN001176676/