Evolution of multilevel caves in the Sierra de Atapuerca (Burgos, Spain) and its relation to human occupation - Ortega Martínez, Ana Isabel; Benito-Calvo, Alfonso; Pérez-González, Alfredo; Martín-Merino, Miguel Ángel; Pérez-Martínez, Raquel; Parés, Josep María; Aranburu Artano, Arantza; Arsuaga, Juan Luis; Bermúdez de Castro, José María; Carbonell, Eudald (2013)