@incollection{JEDP_1976____A4_0,
     author = {Pierre Bolley and Jacques Camus},
     title = {R\'egularit\'e pour des syst\`emes \`a coefficients constants},
     booktitle = {},
     series = {Journ\'ees \'equations aux d\'eriv\'ees partielles},
     eid = {4},
     pages = {1--19},
     publisher = {\'Ecole polytechnique},
     year = {1976},
     language = {fr},
     url = {https://proceedings.centre-mersenne.org/item/JEDP_1976____A4_0/}
}