@article{M2AN_1999__33_3_517_0,
     author = {Benedetto, Dario and Caglioti, Emanuele and Libero, Roberto},
     title = {Non-trapping sets and {Huygens} principle},
     journal = {ESAIM: Mathematical Modelling and Numerical Analysis },
     pages = {517--530},
     publisher = {EDP-Sciences},
     volume = {33},
     number = {3},
     year = {1999},
     mrnumber = {1713236},
     zbl = {0935.35167},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/M2AN_1999__33_3_517_0/}
}