@article{ZNSL_1997_239_a16,
     author = {A. V. Popov},
     title = {Transparent boundaries for the parabolic wave equation},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {211--217},
     year = {1997},
     volume = {239},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1997_239_a16/}
}