@article{CM_1990__74_2_157_0,
     author = {Vaserstein, L. N.},
     title = {On normal subgroups of $\mathrm {GL}_2$ over rings with many units},
     journal = {Compositio Mathematica},
     pages = {157--164},
     publisher = {Kluwer Academic Publishers},
     volume = {74},
     number = {2},
     year = {1990},
     mrnumber = {1047737},
     zbl = {0697.20040},
     language = {en},
     url = {http://archive.numdam.org/item/CM_1990__74_2_157_0/}
}