@article{ASNSP_1979_4_6_1_69_0,
     author = {Andreotti, Aldo and Nacinovich, Mauro},
     title = {On the envelope of regularity for solutions of homogeneous systems of linear partial differential operators},
     journal = {Annali della Scuola Normale Superiore di Pisa - Classe di Scienze},
     pages = {69--141},
     publisher = {Scuola normale superiore},
     volume = {Ser. 4, 6},
     number = {1},
     year = {1979},
     mrnumber = {529476},
     zbl = {0394.35017},
     language = {en},
     url = {http://archive.numdam.org/item/ASNSP_1979_4_6_1_69_0/}
}