@article{MZ_1967__98_170730,
     author = {Helmut R\"ohrl},
     title = {Zur {Definition} quadratischer {Formen.}},
     journal = {Mathematische Zeitschrift},
     pages = {42--45},
     publisher = {mathdoc},
     volume = {98},
     year = {1967},
     zbl = {0146.25903},
     url = {http://geodesic.mathdoc.fr/item/MZ_1967__98_170730/}
}