@article{SJL_1965-1966___2_17_0,
     author = {Lions, J. L.},
     title = {Sur un nouveau type de probl\`eme non lin\'eaire pour op\'erateurs hyperboliques du 2e ordre},
     journal = {S\'eminaire Jean Leray},
     pages = {17--33},
     publisher = {Coll\`ege de France},
     number = {2},
     year = {1965-1966},
     language = {fr},
     url = {http://archive.numdam.org/item/SJL_1965-1966___2_17_0/}
}