@article{ASENS_1890_3_7__19_0,
     author = {Guichard, C.},
     title = {Sur une classe particuli\`ere d'\'equations aux d\'eriv\'ees partielles dont les invariants sont \'egaux},
     journal = {Annales scientifiques de l'\'Ecole Normale Sup\'erieure},
     pages = {19--22},
     publisher = {Elsevier},
     volume = {3e s{\'e}rie, 7},
     year = {1890},
     doi = {10.24033/asens.333},
     language = {fr},
     url = {http://www.numdam.org/articles/10.24033/asens.333/}
}