@article{DAN_1969_186_4_a15,
     author = {V. I. Koroza},
     title = {A variation method for wave propagation boundary value problem},
     journal = {Doklady Akademii Nauk},
     pages = {795--798},
     publisher = {mathdoc},
     volume = {186},
     number = {4},
     year = {1969},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1969_186_4_a15/}
}