A combinatorial approach to singularities of normal surfaces
In this paper we study generic coverings of branched over a curve s.t. the total space is a normal analytic surface, in terms of a graph representing the monodromy of the covering, called monodromy graph. A complete description of the monodromy graphs and of the local fundamental groups is found in case the branch curve is (with ) and the degree of the cover is equal to or .