@article{article0082f39e,
title   = {Morse theory for normal geodesics in sub-Riemannian manifolds with codimension one distributions},
author = {Giambó, Roberto and Giannoni, Fábio and Piccione, Paolo and Tausk, Daniel Victor},
year = {2003},
doi = {10.12775/tmna.2003.016},
journal   = {Topological Methods in Nonlinear Analysis}
}