@article{JRAM_1835__13_146938,
     author = {E. Gudermann},
     title = {Beitrag zur analytischen {Sph\"arik.}},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {262--269},
     year = {1835},
     volume = {13},
     language = {de},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1835__13_146938/}
}