@article{MZ_1990__205_3_174199,
     author = {Matti Vuorinen},
     title = {Quadruples and spatial quasiconformal mappings.},
     journal = {Mathematische Zeitschrift},
     pages = {617--628},
     publisher = {mathdoc},
     volume = {205},
     number = {3},
     year = {1990},
     zbl = {0692.30018},
     url = {http://geodesic.mathdoc.fr/item/MZ_1990__205_3_174199/}
}