Universidad de Zaragoza Repository

@article{Calvo:60643,
      author        = "Calvo, Guiomar and Mudd, Gavin and Valero, Alicia and
                       Valero, Antonio",
      title         = "{Decreasing Ore Grades in Global Metallic Mining: A
                       Theoretical Issue or a Global Reality?}",
      year          = "2016",
}