@article{DAN_1994_334_2_a8,
     author = {L. M. Zubov and A. N. Rudev},
     title = {Conditions for the existence of longitudinal waves in an},
     journal = {Doklady Akademii Nauk},
     pages = {156--158},
     publisher = {mathdoc},
     volume = {334},
     number = {2},
     year = {1994},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1994_334_2_a8/}
}