@article{SM_1988_61_2_a4,
     author = {R. K. Romanovskii},
     title = {Exponentially splittable hyperbolic systems with two independent variables},
     journal = {Sbornik. Mathematics},
     pages = {335--349},
     publisher = {mathdoc},
     volume = {61},
     number = {2},
     year = {1988},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1988_61_2_a4/}
}