First Author:   Francesco Angelini Department of Statistics, University of Bologna francesco.angelini7@unibo.it   Piazza Teatini, 10 Rimini, 47921, Italy   +39 0541 434050(Phone) +39 0541 434050(Fax) www.unibo.it/sitoweb/francesco.angelini7 Second Author: Massimiliano Castellani Department of Statistics, University of Bologna m.castellani@unibo.it   Rimini, 47921, Italy