@article{JOLT_2012_22_1_a10,
     author = {Malika Ait Ben Haddou and Mohamed Boucetta and Hicham Lebzioui},
     title = {Left-invariant {Lorentzian} {Flat} {Metrics} on {Lie} {Groups}},
     journal = {Journal of Lie Theory},
     pages = {269--289},
     year = {2012},
     volume = {22},
     number = {1},
     url = {http://geodesic.mathdoc.fr/item/JOLT_2012_22_1_a10/}
}