1. Adams, A. 1915. The Plateau Peoples of South America: An Essay in Ethnic Psychology. London: George Routledge & Sons. http://archive.org/details/cu31924019964489.
2. Ameghino, F. 1880. Antigüedad del Hombre en el Plata. Volume I. Paris: G. Masson and Buenos Aires: Igon Hermanos. (of a 1918 edition). http://archive.org/details/laantigedaddel01ameg.