A factorization of regular generalized Nevanlinna functions

Let Q be a regular operator valued generalized Nevanlinna function with negative index kappa, i.e. Q is an element of N-kappa(H) It is shown that then there exists a rational function B(z), which collects the generalized poles and zeros of Q that are not of positive type such that the function B((z) over bar)*Q(z)B(z) belongs to the Nevanlinna class N-0(H).