@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/}
}