@article{ASENS_1929_3_46__283_0,
     author = {Goursat, \'Etienne},
     title = {Les caract\'eristiques doubles et le probl\`eme de la d\'eformation des surfaces},
     journal = {Annales scientifiques de l'\'Ecole Normale Sup\'erieure},
     pages = {283--344},
     publisher = {Elsevier},
     volume = {3e s{\'e}rie, 46},
     year = {1929},
     doi = {10.24033/asens.796},
     language = {fr},
     url = {http://archive.numdam.org/articles/10.24033/asens.796/}
}