@article{GDZPPN002480212,
title = {Norms in Quadratic Fields and Their Relations to Non Commuting 2x2 Matrices I.},
journal = {Monatshefte f\"ur Mathematik},
volume = {82},
year = {1976},
pages = {253-256},
zbl = {0334.12009},
url = {http://dml.mathdoc.fr/item/GDZPPN002480212}
}
Taussky, Olga. Norms in Quadratic Fields and Their Relations to Non Commuting 2x2 Matrices I.. Monatshefte für Mathematik, Tome 82 (1976) pp. 253-256. http://gdmltest.u-ga.fr/item/GDZPPN002480212/