@article{MAN_1996__305_2_182991,
     author = {Dirk Mittenhuber},
     title = {On the causal structure of {Lorentzian} {Lie} groups. {A} globality theorem for {Lorentzian} cones in certain solvable {Lie} algebras.},
     journal = {Mathematische Annalen},
     pages = {343--354},
     publisher = {mathdoc},
     volume = {305},
     number = {2},
     year = {1996},
     zbl = {0854.22007},
     url = {http://geodesic.mathdoc.fr/item/MAN_1996__305_2_182991/}
}