@article{DAN_1968_180_2_a21,
     author = {V. N. Zharkov and V. M. Lyubimov},
     title = {Perturbation theory for spheroidal oscillations of the {Earth}},
     journal = {Doklady Akademii Nauk},
     pages = {347--349},
     publisher = {mathdoc},
     volume = {180},
     number = {2},
     year = {1968},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1968_180_2_a21/}
}