@article{ETNA_2008__29__a9,
     author = {Bolten,  Matthias},
     title = {Hierarchical grid coarsening for the solution of the {Poisson} equation in free space},
     journal = {Electronic transactions on numerical analysis},
     year = {2008},
     volume = {29},
     zbl = {1175.35035},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/ETNA_2008__29__a9/}
}