@article{MAN_1924__91_159046,
     author = {H. Tietze},
     title = {Beitr\"age zur allgemeinen {Topologie.} {II.} {\"Uber} die {Einf\"uhrung} uneigentlicher {Elemente}},
     journal = {Mathematische Annalen},
     pages = {210--224},
     publisher = {mathdoc},
     volume = {91},
     year = {1924},
     zbl = {50.0658.04},
     url = {http://geodesic.mathdoc.fr/item/MAN_1924__91_159046/}
}