@article{DAN_1971_201_1_a1,
     author = {V. A. Borovikov},
     title = {An upper bound for the existence time of the smooth solution of a quasi-linear hyperbolic system},
     journal = {Doklady Akademii Nauk},
     pages = {12--15},
     publisher = {mathdoc},
     volume = {201},
     number = {1},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1971_201_1_a1/}
}