@article{MAN_1967__174_161625,
     author = {W. OBERSCHELP},
     title = {Kombinatorische {Anzahlbestimmungen} in {Relationen.}},
     journal = {Mathematische Annalen},
     pages = {53--78},
     publisher = {mathdoc},
     volume = {174},
     year = {1967},
     zbl = {0155.35002},
     url = {http://geodesic.mathdoc.fr/item/MAN_1967__174_161625/}
}