@article{TMF_1978_34_1_a5,
     author = {M. A. Braun},
     title = {Perturbation theory for level shifts and transition probabilities in a~relativistic two-electron system},
     journal = {Teoreti\v{c}eska\^a i matemati\v{c}eska\^a fizika},
     pages = {59--68},
     publisher = {mathdoc},
     volume = {34},
     number = {1},
     year = {1978},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TMF_1978_34_1_a5/}
}