@article{DAN_1969_189_5_a3,
     author = {V. Ya. Ivrii},
     title = {Exponential decay of the solution of the wave equation outside an almost star-shaped region},
     journal = {Doklady Akademii Nauk},
     pages = {938--940},
     publisher = {mathdoc},
     volume = {189},
     number = {5},
     year = {1969},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1969_189_5_a3/}
}