@article{MZ_1919__4_167523,
     author = {O., Sz\'asz},
     title = {\"Uber {Potenzreihen} und {Bilinearformen}},
     journal = {Mathematische Zeitschrift},
     pages = {163--176},
     publisher = {mathdoc},
     volume = {4},
     year = {1919},
     zbl = {47.0273.01},
     url = {http://geodesic.mathdoc.fr/item/MZ_1919__4_167523/}
}