@article{PMF_1904_15_1_a2,
     author = {Guldberg, Alf},
     title = {Ueber simultane lineare differenzengleichungen},
     journal = {Prace Matematyczno-Fizyczne},
     pages = {23--28},
     publisher = {mathdoc},
     volume = {15},
     number = {1},
     year = {1904},
     language = {de},
     url = {http://geodesic.mathdoc.fr/item/PMF_1904_15_1_a2/}
}