@article{CM_1992__83_3_347_0, author = {Borel, Armand and Prasad, Gopal}, title = {Values of isotropic quadratic forms at $S$-integral points}, journal = {Compositio Mathematica}, pages = {347--372}, publisher = {Kluwer Academic Publishers}, volume = {83}, number = {3}, year = {1992}, mrnumber = {1175945}, zbl = {0777.11008}, language = {en}, url = {http://archive.numdam.org/item/CM_1992__83_3_347_0/} }