1. Arqueos Research Group, Archaeology Section, Department of History; University of Oviedo; C/ Amparo Pedregal s/n, Campus del Milán 33011 Oviedo Spain
2. Department of Chemical and Environmental Engineering; University of Oviedo; C/ Julián Clavería s/n 33071 Oviedo Spain
3. Spectroscopy and Spectrometry Unit of the Scientific and Technological Resources Section; University of Oviedo; C/ Julián Clavería s/n 33071 Oviedo Spain