@article{DAN_1967_177_6_a13,
     author = {A. M. Ermolaev},
     title = {Perturbation theory for the expansion coefficients of two-electron wave function},
     journal = {Doklady Akademii Nauk},
     pages = {1302--1305},
     publisher = {mathdoc},
     volume = {177},
     number = {6},
     year = {1967},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1967_177_6_a13/}
}