@article{CMH_1959__33_139160,
     author = {Walter Ledermann},
     title = {An arithmetical property of quadratic forms.},
     journal = {Commentarii mathematici Helvetici},
     pages = {34--37},
     publisher = {mathdoc},
     volume = {33},
     year = {1959},
     zbl = {0082.25803},
     url = {http://geodesic.mathdoc.fr/item/CMH_1959__33_139160/}
}