@article{BSMF_1906__34__48_0,
     author = {Hadamard},
     title = {Sur les caract\'eristiques des syst\`emes aux d\'eriv\'ees partielles},
     journal = {Bulletin de la Soci\'et\'e Math\'ematique de France},
     pages = {48--52},
     publisher = {Soci\'et\'e math\'ematique de France},
     volume = {34},
     year = {1906},
     doi = {10.24033/bsmf.768},
     language = {fr},
     url = {http://www.numdam.org/articles/10.24033/bsmf.768/}
}