@article{IVM_1962_1_a14,
     author = {A. Z. Petrov and V. R. Kaigorodov and V. N. Abdullin},
     title = {Classification of gravitational fields of general type in terms of the motion {groups.~IV}},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {130--142},
     publisher = {mathdoc},
     number = {1},
     year = {1962},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1962_1_a14/}
}