@article{SJL_1969-1970___1_1_0,
     author = {Malgrange, Bernard},
     title = {Pseudo-groupes de {Lie} elliptiques},
     journal = {S\'eminaire sur les \'equations aux d\'eriv\'ees partielles},
     pages = {1--59},
     year = {1969-1970},
     publisher = {Coll\`ege de France},
     number = {1},
     language = {fr},
     url = {https://www.numdam.org/item/SJL_1969-1970___1_1_0/}
}