@article{JMPA_1845_1_10__251_0,
     author = {Roberts, Michael},
     title = {Note sur deux syst\`emes g\'en\'eraux de trajectoires orthogonales},
     journal = {Journal de Math\'ematiques Pures et Appliqu\'ees},
     pages = {251--256},
     publisher = {Gauthier-Villars},
     volume = {1e s{\'e}rie, 10},
     year = {1845},
     language = {fr},
     url = {http://www.numdam.org/item/JMPA_1845_1_10__251_0/}
}