@article{MAN_1909__67_158419,
     author = {Joseph Wellstein},
     title = {Von den {Differentialgleichungen} der projektiven {Invarianten.}},
     journal = {Mathematische Annalen},
     pages = {490--497},
     publisher = {mathdoc},
     volume = {67},
     year = {1909},
     zbl = {40.0152.01},
     url = {http://geodesic.mathdoc.fr/item/MAN_1909__67_158419/}
}