A.A. Agrachev, El Alaoui El-Houcine Chakir, Gauthier Jean-Paul, I. Kupka, Generic singularities of sub-Riemannian metrics on R3

Title: Generic singularities of sub-Riemannian metrics on R3
Authors: A.A. Agrachev, El Alaoui El-Houcine Chakir, Gauthier Jean-Paul, I. Kupka
Journal title: C. R. Acad. Sci. Paris Sér. I Math.
Year: 1996
Issue: 4
Volume: 322
Pages: 377–384