@article{MZ_1920__6_167567,
     author = {O., Perron},
     title = {\"Uber nichthomogene lineare {Differentialgleichungen}},
     journal = {Mathematische Zeitschrift},
     pages = {161--2},
     publisher = {mathdoc},
     volume = {6},
     year = {1920},
     zbl = {47.0406.03},
     url = {http://geodesic.mathdoc.fr/item/MZ_1920__6_167567/}
}