@article{ASENS_1970_4_3_2_185_0,
     author = {Bardos, Claude},
     title = {Probl\`emes aux limites pour les \'equations aux d\'eriv\'ees partielles du premier ordre \`a coefficients r\'eels ; th\'eor\`emes d'approximation ; application \`a l'\'equation de transport},
     journal = {Annales scientifiques de l'\'Ecole Normale Sup\'erieure},
     pages = {185--233},
     publisher = {Elsevier},
     volume = {4e s{\'e}rie, 3},
     number = {2},
     year = {1970},
     doi = {10.24033/asens.1190},
     mrnumber = {43 #683},
     zbl = {0202.36903},
     language = {fr},
     url = {http://www.numdam.org/articles/10.24033/asens.1190/}
}