@article{MZ_1969__109_171141,
     author = {Kay S\"orensen},
     title = {Zum {Begriff} des topologischen projektiven {Raumes.}},
     journal = {Mathematische Zeitschrift},
     pages = {239--245},
     publisher = {mathdoc},
     volume = {109},
     year = {1969},
     zbl = {0181.23303},
     url = {http://geodesic.mathdoc.fr/item/MZ_1969__109_171141/}
}