@article{JRAM_1893__111_148867,
     author = {Leo K\"onigsberger},
     title = {Ueber die {Irreducibilit\"at} der algebraischen partiellen {Differentialgleichungssysteme.}},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {1--25},
     publisher = {mathdoc},
     volume = {111},
     year = {1893},
     zbl = {25.0597.01},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1893__111_148867/}
}