@article{ETNA_1996__4__a5,
     author = {Casarin, Mario A. and Widlund, Olof B.},
     title = {A hierarchical preconditioner for the mortar finite element method},
     journal = {Electronic transactions on numerical analysis},
     pages = {75--88},
     publisher = {mathdoc},
     volume = {4},
     year = {1996},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ETNA_1996__4__a5/}
}