@article{SEDP_1983-1984____A11_0,
     author = {Nourrigat, J.},
     title = {Approximation des syst\`emes d'op\'erateurs pseudodiff\'erentiels},
     journal = {S\'eminaire Goulaouic-Schwartz},
     note = {talk:11},
     pages = {1--13},
     year = {1983-1984},
     publisher = {Ecole Polytechnique, Centre de Math\'ematiques},
     zbl = {0543.35106},
     language = {fr},
     url = {https://www.numdam.org/item/SEDP_1983-1984____A11_0/}
}