@article{MZ_1992__209_2_251867,
     author = {Louis Mah\'e},
     title = {Level and {Pythagoras} number of some geometric rings {(Erratum).}},
     journal = {Mathematische Zeitschrift},
     pages = {481--484},
     year = {1992},
     volume = {209},
     number = {2},
     zbl = {0773.11025},
     url = {http://geodesic.mathdoc.fr/item/MZ_1992__209_2_251867/}
}