@article{IM_1989__98_1_143736,
     author = {G.A. Margulis and S.G. Dani},
     title = {Values of quadratic forms at primitive integral points.},
     journal = {Inventiones mathematicae},
     pages = {405--424},
     publisher = {mathdoc},
     volume = {98},
     number = {1},
     year = {1989},
     zbl = {0682.22008},
     url = {http://geodesic.mathdoc.fr/item/IM_1989__98_1_143736/}
}