@article{ZNSL_1986_156_a8,
     author = {N. Ya. Kirpichnikova},
     title = {On asymptotic behavior of non-stationary wave field singularities near the space-time caustic},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {98--108},
     year = {1986},
     volume = {156},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1986_156_a8/}
}