@article{MZ_1968__104_170933,
     author = {Oddvar Iden},
     title = {Free {Planes.} {II.}},
     journal = {Mathematische Zeitschrift},
     pages = {98--98},
     publisher = {mathdoc},
     volume = {104},
     year = {1968},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/MZ_1968__104_170933/}
}