On three-parameter families of Filippov systems -- the fold-saddle   singularity
  This paper presents results concerning bifurcations of 2D piecewise-smooth vector fields. In particular, the generic unfoldings of codimension three fold-addle singularities of Filippov systems, where a boundary-saddle and a fold coincide, are considered and the bifurcation diagrams exhibited. 
Tiago de Carvalho, Claudio Aguinaldo Buzzi and Marco Antonio Teixeira
math.DS