@article{NUMA_1985__46_133001,
     author = {H. Schippers},
     title = {Multigrid {Methods} for {Boundary} {Integral} {Equations.}},
     journal = {Numerische Mathematik},
     pages = {351--364},
     publisher = {mathdoc},
     volume = {46},
     year = {1985},
     zbl = {0543.65015},
     url = {http://geodesic.mathdoc.fr/item/NUMA_1985__46_133001/}
}