@article{ZNSL_1973_34_a8,
     author = {V. B. Filippov},
     title = {On the exact justification of the short wave approximation in a~shadow region},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {142--205},
     publisher = {mathdoc},
     volume = {34},
     year = {1973},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1973_34_a8/}
}