@article{RSMUP_1974__51__105_0,
     author = {Bratti, Giuliano},
     title = {Sul comportamento degli operatori differenziali ipoellittici, a coefficienti costanti, sopra i {\guillemotleft} wave front sets {\guillemotright}},
     journal = {Rendiconti del Seminario Matematico della Universit\`a di Padova},
     pages = {105--111},
     publisher = {Seminario Matematico of the University of Padua},
     volume = {51},
     year = {1974},
     mrnumber = {387802},
     zbl = {0309.35027},
     language = {it},
     url = {http://archive.numdam.org/item/RSMUP_1974__51__105_0/}
}