@article{10_4153_CMB_1958_018_0,
     author = {Schwerdtfeger, H.},
     title = {On the {Discriminant} {x'Ax.y'Ay-(x'Ay)2}},
     journal = {Canadian mathematical bulletin},
     pages = {175--179},
     year = {1958},
     volume = {1},
     number = {3},
     doi = {10.4153/CMB-1958-018-0},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-1958-018-0/}
}