@article{MAN_1929__101_159354,
     author = {K. Popoff},
     title = {Sur les int\'egrales des \'equations diff\'erentielles consid\'er\'ees comme fonctions des param\`etres},
     journal = {Mathematische Annalen},
     pages = {570--578},
     publisher = {mathdoc},
     volume = {101},
     year = {1929},
     zbl = {55.0842.02},
     url = {http://geodesic.mathdoc.fr/item/MAN_1929__101_159354/}
}