@article{JRAM_1883__94_148543,
     author = {Wilhelm Stahl},
     title = {Zur {Polarentheorie} der {Complexen} zweiten {Grades.}},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {319--328},
     publisher = {mathdoc},
     volume = {94},
     year = {1883},
     zbl = {15.0557.03},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1883__94_148543/}
}