@article{SEDP_1982-1983____A2_0,
     author = {Friedlander, F. G.},
     title = {A unique continuation theorem for the wave equation in the exterior of a characteristic cone},
     journal = {S\'eminaire \'Equations aux d\'eriv\'ees partielles (Polytechnique) dit aussi "S\'eminaire Goulaouic-Schwartz"},
     note = {talk:2},
     pages = {1--10},
     publisher = {Ecole Polytechnique, Centre de Math\'ematiques},
     year = {1982-1983},
     mrnumber = {716890},
     zbl = {0536.35009},
     language = {en},
     url = {http://archive.numdam.org/item/SEDP_1982-1983____A2_0/}
}