The singularities of the maps associated with Milnor fibrations
  Milnor fibrations have been studied since 1960's. In this paper, we study singular points of differentiable maps, called Milnor fibration product maps, obtained by several Milnor fibrations. We give a characterization of singular points of such product maps, and for the case of certain weighted homogeneous polynomials, a criterion for a fold point together with its index. 
Daiki Sumida
math.GT