@article{SJL_1971____A6_0,
     author = {Vaillant, Jean},
     title = {Remarques sur les syst\`emes fortement hyperboliques},
     journal = {S\'eminaire Jean Leray},
     note = {talk:6},
     pages = {1--24},
     publisher = {Coll\`ege de France},
     year = {1971},
     language = {fr},
     url = {http://www.numdam.org/item/SJL_1971____A6_0/}
}