@article{MZ_1920__7_167580,
     author = {A., Loewy},
     title = {Begleitmatrizen und lineare homogene {Differentialausdr\"ucke}},
     journal = {Mathematische Zeitschrift},
     pages = {58--125},
     year = {1920},
     volume = {7},
     zbl = {47.0408.02},
     url = {http://geodesic.mathdoc.fr/item/MZ_1920__7_167580/}
}