Metalurgia y tecnología de oro y platino y Proceso de dorado y metalurgia de cobre y plomo entre los indios precolombinos - Bergsøe, Paul 1872-1963 (Clemencia Plazas, 1982)
Translation of "The metallurgy and technology of gold and platinum among the pre-Columbian Indians", Copenhagen 1937 and "The gilding process and the metallurgy of copper and lead among the pre-Columbian Indians", Copenhagen 1938