@article{MZ_1929__30_168129,
     author = {K. Knopp},
     title = {Neuere {S\"atze} \"uber {Reihen} mit positiven {Gliedern}},
     journal = {Mathematische Zeitschrift},
     pages = {387--403},
     publisher = {mathdoc},
     volume = {30},
     year = {1929},
     zbl = {55.0730.06},
     url = {http://geodesic.mathdoc.fr/item/MZ_1929__30_168129/}
}