1. Generic bifurcations of low codimension of planar Filippov Systems
2. Smoothing continuous flows and the converse of Denjoy–Schwartz theorem;Gutierrez;An. Acad. Brasil. Ci.,1979
3. [2] C. A. Buzzi , T. de Carvalho and R. D. Euzebio . On Poincare–Bendixson theorem and non-trivial minimal sets in planar nonsmooth vector fields. Preprint, 2013, http://arxiv.org/pdf/1307.6825v1.pdf.