@article{COCV_1999__4__245_0,
     author = {Bonnard, Bernard and Chyba, Monique},
     title = {M\'ethodes g\'eom\'etriques et analytiques pour \'etudier l'application exponentielle, la sph\`ere et le front d'onde en g\'eom\'etrie sous-riemannienne dans le cas {Martinet}},
     journal = {ESAIM: Control, Optimisation and Calculus of Variations},
     pages = {245--334},
     publisher = {EDP-Sciences},
     volume = {4},
     year = {1999},
     mrnumber = {1696290},
     zbl = {0929.53016},
     language = {fr},
     url = {http://www.numdam.org/item/COCV_1999__4__245_0/}
}