@article{GDZPPN001170783, title = {The Finite Element Method with Lagrangian Multipliers.}, journal = {Numerische Mathematik}, volume = {19}, year = {1972}, pages = {179-192}, zbl = {0258.65108}, url = {http://dml.mathdoc.fr/item/GDZPPN001170783} }
Babuska, Ivo. The Finite Element Method with Lagrangian Multipliers.. Numerische Mathematik, Tome 19 (1972) pp. 179-192. http://gdmltest.u-ga.fr/item/GDZPPN001170783/