@article{GDZPPN001180452,
title = {Numerical Solution of the Obstacle Problem by the Penalty Method. Part II. Time-Dependent Problem.},
journal = {Numerische Mathematik},
volume = {50},
year = {1986},
pages = {255-268},
zbl = {0592.65039},
url = {http://dml.mathdoc.fr/item/GDZPPN001180452}
}
Scholz, Reinhard. Numerical Solution of the Obstacle Problem by the Penalty Method. Part II. Time-Dependent Problem.. Numerische Mathematik, Tome 50 (1986) pp. 255-268. http://gdmltest.u-ga.fr/item/GDZPPN001180452/