@article{DAN_1957_115_1_a1,
     author = {V. M. Borok},
     title = {The reduction of a system of linear partial differential equations with constant coefficients to the normal form},
     journal = {Doklady Akademii Nauk},
     pages = {13--16},
     publisher = {mathdoc},
     volume = {115},
     number = {1},
     year = {1957},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1957_115_1_a1/}
}