@article {boscain2010normal,
	title = {A normal form for generic 2-dimensional almost-Riemannian structures at a tangency point},
	journal = {arXiv preprint arXiv:1008.5036},
	year = {2010},
	author = {Ugo Boscain and Gr{\'e}goire Charlot and Roberta Ghezzi}
}
