@article{JRAM_1990__406_153219,
     author = {H.-D. Alber and Jeffrey Cooper},
     title = {Quasilinear hyperbolic 2 x 2 systems with a free, damping boundary condition.},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {10--43},
     year = {1990},
     volume = {406},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1990__406_153219/}
}