@article{GDZPPN002315467, title = {Isometric Immersions of Lorentzian Space Forms.}, journal = {Mathematische Annalen}, volume = {237}, year = {1978}, pages = {125-136}, zbl = {0354.53046}, url = {http://dml.mathdoc.fr/item/GDZPPN002315467} }
Nomizu, Katsumi; Graves, Larry. Isometric Immersions of Lorentzian Space Forms.. Mathematische Annalen, Tome 237 (1978) pp. 125-136. http://gdmltest.u-ga.fr/item/GDZPPN002315467/