@article{MS2_1987__61_2_186100,
     author = {Dale Clarke Hernquist},
     title = {Smoothly symmetrizable hyperbolic systems of partial differential equations.},
     journal = {Mathematica Scandinavica},
     pages = {262--275},
     publisher = {mathdoc},
     volume = {61},
     number = {2},
     year = {1987},
     zbl = {0656.35080},
     url = {http://geodesic.mathdoc.fr/item/MS2_1987__61_2_186100/}
}