@article{ZNSL_1988_173_a1,
     author = {V. M. Babich},
     title = {Wave propagation throgh a thin layer},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {20--29},
     publisher = {mathdoc},
     volume = {173},
     year = {1988},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1988_173_a1/}
}