@article{DE_1966_2_5_a9,
     author = {A. A. Grib},
     title = {The symmetry group of solutions of the {Klein--Gordon} equation in the exterior vector field},
     journal = {Differencialʹnye uravneni\^a},
     pages = {688--694},
     publisher = {mathdoc},
     volume = {2},
     number = {5},
     year = {1966},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1966_2_5_a9/}
}