1. Department of Physical Geography and CEACTEMA, University of Jaén, 23071 Jaén, Spain
2. Department of Geography, St. Ignatius of Loyola High School, 31004 Pamplona, Spain
3. Department of Geography, National University of Distance Education (UNED), 28015 Madrid, Spain
4. Polytechnic School of Huesca, University of Zaragoza, 22007 Huesca, Spain
5. Centro Universitario de la Defensa de Zaragoza, 50090 Zaragoza, Spain