@article{DAN_1978_239_3_a12,
     author = {L. N. Maurin},
     title = {Lowering of the order of a system of equations of hydrodynamic type allowing simple degeneracy},
     journal = {Doklady Akademii Nauk},
     pages = {550--553},
     publisher = {mathdoc},
     volume = {239},
     number = {3},
     year = {1978},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1978_239_3_a12/}
}