@article{AIHPA_1977__27_1_61_0,
     author = {Leipold, Gerhard and Walker, Martin},
     title = {Boundary conditions at past null infinity for zero-rest-mass fields including gravitation},
     journal = {Annales de l'I.H.P. Physique th\'eorique},
     pages = {61--71},
     publisher = {Gauthier-Villars},
     volume = {27},
     number = {1},
     year = {1977},
     zbl = {0361.53028},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AIHPA_1977__27_1_61_0/}
}