@article{MAN_1935__111_159801,
     author = {L. Hopf},
     title = {Fortsetzungsrelationen bei den {L\"osungen} linearer {Differentialgleichungen.}},
     journal = {Mathematische Annalen},
     pages = {678--712},
     publisher = {mathdoc},
     volume = {111},
     year = {1935},
     zbl = {0012.25602},
     url = {http://geodesic.mathdoc.fr/item/MAN_1935__111_159801/}
}