@article{SLS_1954-1955__2__A6_0,
     author = {Schwartz, L.},
     title = {Conditions d'ellipticit\'e},
     journal = {S\'eminaire Schwartz},
     note = {talk:4},
     pages = {1--7},
     publisher = {Secr\'etariat math\'ematique},
     volume = {2},
     year = {1954-1955},
     language = {fr},
     url = {http://www.numdam.org/item/SLS_1954-1955__2__A6_0/}
}