Department of Statistics and Econometrics, University of Carlos III, Madrid, Spain.|Department of Statistics and Econometrics, University of Carlos III, Madrid, Spain.|Department of Statistics and Econometrics, University of Carlos III, Madrid, Spain.|Department of Statistics and Econometrics, University of Carlos III, Madrid, Spain.|Department of Statistics and Econometrics, University of Carlos III, Madrid, Spain.|Department of Statistics and Econometrics, University of Carlos III, Madrid, Spain.|Department of Statistics and Econometrics, University of Carlos III, Madrid, Spain.