@article{PORMA_1982__41_1-4_115511,
     author = {P\'ovoas, M.},
     title = {Boundary control of a symmetric hyperbolic system with nonlinear boundary conditions},
     journal = {Portugaliae mathematica},
     pages = {393--403},
     publisher = {mathdoc},
     volume = {41},
     number = {1-4},
     year = {1982},
     mrnumber = {0766867},
     zbl = {0553.49005},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PORMA_1982__41_1-4_115511/}
}