Nilpotent singularities of foliations of generalized Poincaré–Dulac type

We will review several results concerning nilpotent singularities of holomorphic foliations in dimension two, and we shall focus in some recent work being done in the case when, in the reduction of singularities of such a foliation, a singularity of Poincaré–Dulac type appears. It is a case that apparently has not been treated yet by the different authors who have studied these singularities.
It is work in progress, in collaboration with Percy Fernández (PUCP, Peru).