@article{SIGMA_2009_5_a78,
     author = {Felipe Leitner},
     title = {About {Twistor} {Spinors} with {Zero} in {Lorentzian} {Geometry}},
     journal = {Symmetry, integrability and geometry: methods and applications},
     year = {2009},
     volume = {5},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SIGMA_2009_5_a78/}
}