@article{DAN_1984_276_6_a5,
     author = {N. G. Marchuk},
     title = {On a method of reducing the wave equation to a system of first order equations},
     journal = {Doklady Akademii Nauk},
     pages = {1309--1311},
     publisher = {mathdoc},
     volume = {276},
     number = {6},
     year = {1984},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1984_276_6_a5/}
}