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Agrachev, A. A.; Boscain, U.; Charlot, G.; Ghezzi, R.; Sigalotti, M. Two-dimensional almost-Riemannian structures with tangency points. (English) Zbl 1192.53029 Ann. Inst. Henri Poincaré, Anal. Non Linéaire 27, No. 3, 793-807 (2010). MSC: 53C15 53B20 PDF BibTeX XML Cite \textit{A. A. Agrachev} et al., Ann. Inst. Henri Poincaré, Anal. Non Linéaire 27, No. 3, 793--807 (2010; Zbl 1192.53029) Full Text: DOI arXiv