@article{MOMA_1976__82_177782,
     author = {Olga Taussky},
     title = {Norms in {Quadratic} {Fields} and {Their} {Relations} to {Non} {Commuting} 2x2 {Matrices} {I.}},
     journal = {Monatshefte f\"ur Mathematik},
     pages = {253--256},
     publisher = {mathdoc},
     volume = {82},
     year = {1976},
     zbl = {0334.12009},
     url = {http://geodesic.mathdoc.fr/item/MOMA_1976__82_177782/}
}