@article{GDZPPN001171933,
title = {New Error Bounds for the Penalty Method and Extrapolation.},
journal = {Numerische Mathematik},
volume = {22},
year = {1974},
pages = {153-166},
zbl = {0272.65092},
url = {http://dml.mathdoc.fr/item/GDZPPN001171933}
}
King, J.T. New Error Bounds for the Penalty Method and Extrapolation.. Numerische Mathematik, Tome 22 (1974) pp. 153-166. http://gdmltest.u-ga.fr/item/GDZPPN001171933/