@article{CM_1992__82_2_137_0,
     author = {Langmann, Klaus},
     title = {Der {4-Werte-Satz} in der {Zahlentheorie}},
     journal = {Compositio Mathematica},
     pages = {137--142},
     publisher = {Kluwer Academic Publishers},
     volume = {82},
     number = {2},
     year = {1992},
     mrnumber = {1157937},
     zbl = {0784.11010},
     language = {de},
     url = {http://archive.numdam.org/item/CM_1992__82_2_137_0/}
}