@article{DAN_1978_239_4_a3,
     author = {Yu. L. Ershov},
     title = {Valuations of skew fields and the group $SK_1$},
     journal = {Doklady Akademii Nauk},
     pages = {768--771},
     publisher = {mathdoc},
     volume = {239},
     number = {4},
     year = {1978},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1978_239_4_a3/}
}