@article{GDZPPN001185802,
title = {Boundary Lagrange multipliers in finite element methods: error analysis in natural forms.},
journal = {Numerische Mathematik},
volume = {63},
year = {1992},
pages = {1-16},
zbl = {0765.65102},
url = {http://dml.mathdoc.fr/item/GDZPPN001185802}
}
Barbosa, H.J.C.; Hughes, Thomas J.R. Boundary Lagrange multipliers in finite element methods: error analysis in natural forms.. Numerische Mathematik, Tome 63 (1992) pp. 1-16. http://gdmltest.u-ga.fr/item/GDZPPN001185802/