@article{IJAMCS_2011_21_3_a6,
     author = {Hild, P.},
     title = {A sign preserving mixed finite element approximation for contact problems},
     journal = {International Journal of Applied Mathematics and Computer Science},
     pages = {487--498},
     publisher = {mathdoc},
     volume = {21},
     number = {3},
     year = {2011},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IJAMCS_2011_21_3_a6/}
}