@article{10_4153_CMB_1992_047_8,
     author = {Ferr\'andez, Angel},
     title = {Null {2-Type} {Hypersurfaces} in a {Lorentz} {Space}},
     journal = {Canadian mathematical bulletin},
     pages = {354--360},
     year = {1992},
     volume = {35},
     number = {3},
     doi = {10.4153/CMB-1992-047-8},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CMB-1992-047-8/}
}