First Author:   Jaime Alonso-Carrera University of Vigo, Spain jalonso@uvigo.es   Facultad de Ciencias Económicas y Empresariales, Campus As Lagoas-Marcosende Vigo, 36310, Spain   986 813516(Phone) 986 813516(Fax) http://webs.uvigo.es/jalonso Second Author: María-Jesús Freire-Serén University of Vigo, Spain mjfreire@uvigo.es   Facultad de Ciencias Económicas y Empresarialesde, Campus As Lagoas-Marcosende Vigo, 36310, Spain