1. Centro Universitario de la Defensa Zaragoza, Academia General Militar, Ctra. de Huesca s/n, 50090 Zaragoza, Spain
2. GEOFOREST-IUCA, Department of Geography, University of Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza, Spain
3. EiFAB-iuFOR, University of Valladolid, Campus Duques de Soria, 42004 Soria, Spain