@article{MZ_1939__45_168868,
     author = {K., K n o p p},
     title = {Limitierungs - {Umkehrs\"atze} f\"ur {Doppelfolgen}},
     journal = {Mathematische Zeitschrift},
     pages = {573--589},
     year = {1939},
     volume = {45},
     zbl = {0023.02801},
     url = {http://geodesic.mathdoc.fr/item/MZ_1939__45_168868/}
}