@article{TMF_1987_72_2_a5,
     author = {A. A. Belov and V. L. Pokrovskii},
     title = {Effective {Hamiltonian} method and spectrum of a~two-electron atom},
     journal = {Teoreti\v{c}eska\^a i matemati\v{c}eska\^a fizika},
     pages = {219--228},
     publisher = {mathdoc},
     volume = {72},
     number = {2},
     year = {1987},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TMF_1987_72_2_a5/}
}