@article{MAN_1921__84_158875,
     author = {O. Perron},
     title = {\"Uber {Summengleichungen} und {Poincar\'esche} {Differenzengleichungen}},
     journal = {Mathematische Annalen},
     pages = {1--15},
     publisher = {mathdoc},
     volume = {84},
     year = {1921},
     zbl = {48.0479.01},
     url = {http://geodesic.mathdoc.fr/item/MAN_1921__84_158875/}
}