@article{AIHPA_1970__13_4_271_0,
     author = {Papapetrou, A.},
     title = {Les \'equations suppl\'ementaires dans le formalisme de {Newman-Penrose}},
     journal = {Annales de l'I.H.P. Physique th\'eorique},
     pages = {271--286},
     publisher = {Gauthier-Villars},
     volume = {13},
     number = {4},
     year = {1970},
     mrnumber = {285248},
     language = {fr},
     url = {http://geodesic.mathdoc.fr/item/AIHPA_1970__13_4_271_0/}
}