@article{DAN_1989_308_2_a17,
     author = {A. E. Lifshits},
     title = {The echo phenomenon in hydrodynamics},
     journal = {Doklady Akademii Nauk},
     pages = {340--344},
     year = {1989},
     volume = {308},
     number = {2},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1989_308_2_a17/}
}