@article{JMPA_1929_9_8__45_0,
     author = {Buhl, A.},
     title = {Lignes asymptotiques et lignes de courbure},
     journal = {Journal de Math\'ematiques Pures et Appliqu\'ees},
     pages = {45--69},
     publisher = {Gauthier-Villars},
     volume = {9e s{\'e}rie, 8},
     year = {1929},
     language = {fr},
     url = {http://www.numdam.org/item/JMPA_1929_9_8__45_0/}
}