@article{AIHPA_1974__20_3_237_0,
     author = {Rosca, Radu},
     title = {Sur les hypersurfaces isotropes de d\'efaut 1 incluses dans un espace hyperbolique de type normal},
     journal = {Annales de l'institut Henri Poincar\'e. Section A, Physique Th\'eorique},
     pages = {237--243},
     publisher = {Gauthier-Villars},
     volume = {20},
     number = {3},
     year = {1974},
     mrnumber = {385765},
     zbl = {0287.53018},
     language = {fr},
     url = {http://www.numdam.org/item/AIHPA_1974__20_3_237_0/}
}