@article{JRAM_1888__102_148706,
     author = {Joseph Perott},
     title = {Sur l'\'equation {t2-Du2=-1.}},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {185--223},
     publisher = {mathdoc},
     volume = {102},
     year = {1888},
     language = {de},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1888__102_148706/}
}