@article{DAN_1977_233_1_a20,
     author = {G. A. Sobolev and L. B. Slavina},
     title = {Change in the $v_p/v_s$ field before the strong earthquakes of {Kamchatka}},
     journal = {Doklady Akademii Nauk},
     pages = {81--84},
     publisher = {mathdoc},
     volume = {233},
     number = {1},
     year = {1977},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1977_233_1_a20/}
}