@article{IVM_1959_6_a15,
     author = {A. Z. Petrov and V. R. Kaigorodov and V. N. Abdullin},
     title = {Classification of gravitational fields of general type by the group of {motions.~I,~II,~III}},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {118--130},
     publisher = {mathdoc},
     number = {6},
     year = {1959},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1959_6_a15/}
}