@article{JRAM_1892__109_148836,
     author = {W. Heymann},
     title = {Zur {Theorie} der {Differenzengleichungen.}},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {112--117},
     publisher = {mathdoc},
     volume = {109},
     year = {1892},
     zbl = {24.0316.02},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1892__109_148836/}
}