%0 Journal Article %A V. N. Zharkov %A V. M. Lyubimov %T Perturbation theory for spheroidal oscillations of the Earth %J Doklady Akademii Nauk %D 1968 %P 347-349 %V 180 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/item/DAN_1968_180_2_a21/ %G ru %F DAN_1968_180_2_a21