@article{DAN_1979_247_2_a22,
     author = {A. L. Krylov and A. E. Lifshits},
     title = {On natural oscillations of anisotropic media},
     journal = {Doklady Akademii Nauk},
     pages = {347--349},
     publisher = {mathdoc},
     volume = {247},
     number = {2},
     year = {1979},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1979_247_2_a22/}
}