@article{MM2_1969__1_153971,
     author = {Heinz-Dieter Niessen},
     title = {Graphens\"atze f\"ur topologische {R\"aume.}},
     journal = {Manuscripta mathematica},
     pages = {111--124},
     publisher = {mathdoc},
     volume = {1},
     year = {1969},
     zbl = {0167.51204},
     url = {http://geodesic.mathdoc.fr/item/MM2_1969__1_153971/}
}