@article{CMH_1991__66_4_140250,
     author = {Y.L. Xin},
     title = {On the {Gauss} image of a spacelike hypersurface with constant mean curvature in {Minkowski} space.},
     journal = {Commentarii mathematici Helvetici},
     pages = {590--598},
     publisher = {mathdoc},
     volume = {66},
     number = {4},
     year = {1991},
     zbl = {0752.53038},
     url = {http://geodesic.mathdoc.fr/item/CMH_1991__66_4_140250/}
}