@article{MZ_1964__84_170265,
     author = {Hans Hornich},
     title = {Huygenssche {Differentialgleichungen} im {Rn.}},
     journal = {Mathematische Zeitschrift},
     pages = {268--270},
     publisher = {mathdoc},
     volume = {84},
     year = {1964},
     zbl = {0144.13902},
     url = {http://geodesic.mathdoc.fr/item/MZ_1964__84_170265/}
}