@article{DAN_1978_241_5_a3,
     author = {V. Ya. Ivrii},
     title = {The nonclassical propagation of singularities of a solution of the wave equation near a boundary},
     journal = {Doklady Akademii Nauk},
     pages = {1013--1015},
     year = {1978},
     volume = {241},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1978_241_5_a3/}
}