@incollection{JEDP_1977____206_0, author = {Wagschal, Claude}, title = {Probl\`eme de {Cauchy} \`a caract\'eristiques multiples dans les classes de {Gevrey}}, booktitle = {}, series = {Journ\'ees \'equations aux d\'eriv\'ees partielles}, pages = {206--216}, publisher = {Ecole polytechnique}, year = {1977}, mrnumber = {80f:35004}, language = {fr}, url = {http://archive.numdam.org/item/JEDP_1977____206_0/} }