Doctoral thesis (2003) - Mathijs De Weerdt (author) , Henk Sips (promotor) , J-J Meyer (copromotor) , Cees Witteveen (copromotor) , Piet H.L. Bovy (copromotor) , RECM van der Heijden (copromotor) , C Roos (copromotor) , KS Decker (copromotor) , N Roos (copromotor)