1. Department of Urology, IIS-Aragon, Miguel Servet University Hospital, Zaragoza, Spain.
2. Department of Applied Mathematics, Escuela Politécnica de La Almunia, Universidad de Zaragoza, Zaragoza, Spain.
3. Department of Statistical Methods, Institute for Biocomputation and Physics of Complex Systems-BIFI, Universidad de Zaragoza, Zaragoza, Spain.