@book{MSM_1955__129__1_0,
     author = {Heilbronn, Georges},
     title = {Int\'egration des \'equations aux d\'eriv\'ees partielles du second ordre par la m\'ethode de {Drach}},
     series = {M\'emorial des sciences math\'ematiques},
     publisher = {Gauthier-Villars},
     number = {129},
     year = {1955},
     mrnumber = {67294},
     zbl = {0064.09203},
     language = {fr},
     url = {http://archive.numdam.org/item/MSM_1955__129__1_0/}
}