@article{MAN_1941__118_160074,
     author = {O. Bor\"uvka},
     title = {\"Uber {Ketten} von {Faktoroiden}},
     journal = {Mathematische Annalen},
     pages = {41--64},
     year = {1941},
     volume = {118},
     url = {http://geodesic.mathdoc.fr/item/MAN_1941__118_160074/}
}