@article{BSMF_1929__57__204_0,
     author = {Bouligand, G.},
     title = {Sur les trajectoires orthogonales d'une famille de droites},
     journal = {Bulletin de la Soci\'et\'e Math\'ematique de France},
     pages = {204--209},
     publisher = {Soci\'et\'e math\'ematique de France},
     volume = {57},
     year = {1929},
     doi = {10.24033/bsmf.1152},
     language = {fr},
     url = {http://www.numdam.org/articles/10.24033/bsmf.1152/}
}