@article{MAN_1885__25_182616,
     author = {Harnack},
     title = {Ueber den {Inhalt} von {Punktmengen}},
     journal = {Mathematische Annalen},
     pages = {241--250},
     year = {1885},
     volume = {25},
     url = {http://geodesic.mathdoc.fr/item/MAN_1885__25_182616/}
}