@article{DAN_1974_218_5_a20,
     author = {S. Ts. Akopyan and V. N. Zharkov and V. M. Lyubimov},
     title = {Perturbation theory for spheroidal oscillations of the {Earth.} {Second} approximation},
     journal = {Doklady Akademii Nauk},
     pages = {1078--1081},
     publisher = {mathdoc},
     volume = {218},
     number = {5},
     year = {1974},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1974_218_5_a20/}
}