@article{ZNSL_1979_89_a17,
     author = {M. M. Popov},
     title = {Wave field in the caustic region in a~vicinity of a~boundary flex point},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {246--260},
     publisher = {mathdoc},
     volume = {89},
     year = {1979},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1979_89_a17/}
}