@article{DE_1984_20_11_a15,
     author = {V. M. Filippov},
     title = {A variational method for solving boundary value problems for the wave equation},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1961--1968},
     publisher = {mathdoc},
     volume = {20},
     number = {11},
     year = {1984},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1984_20_11_a15/}
}