@article{GDZPPN001170287,
title = {Approximation in the Finite Element Method.},
journal = {Numerische Mathematik},
volume = {19},
year = {1972},
pages = {81-98},
zbl = {0221.65174},
url = {http://dml.mathdoc.fr/item/GDZPPN001170287}
}
Strang, G. Approximation in the Finite Element Method.. Numerische Mathematik, Tome 19 (1972) pp. 81-98. http://gdmltest.u-ga.fr/item/GDZPPN001170287/