@article{MAN_1980__253_163476,
     author = {Jon Kr. Arason},
     title = {Der {Wittring} projektiver {R\"aume.}},
     journal = {Mathematische Annalen},
     pages = {205--212},
     publisher = {mathdoc},
     volume = {253},
     year = {1980},
     zbl = {0431.10011},
     url = {http://geodesic.mathdoc.fr/item/MAN_1980__253_163476/}
}