@article{JDM_1929__38_145838,
     author = {Hellmuth Kneser},
     title = {Geschlossene {Fl\"achen} in dreidimensionalen {Mannigfaltigkeiten.}},
     journal = {Jahresbericht der Deutschen Mathematiker-Vereinigung},
     pages = {248--259},
     publisher = {mathdoc},
     volume = {38},
     year = {1929},
     zbl = {55.0311.03},
     url = {http://geodesic.mathdoc.fr/item/JDM_1929__38_145838/}
}