LINKS www.assomarmomacchine.com confindustria MarmoMacchine www.assomarmistilombardia.it Lombardy Stone Association www.asmave.it Verona stone association www.cosmave.it Versilia Stone Consortium www.centrotravertinoromano.it Institute for the Travertino of Rome www.consorziomarmistichiampo.com Chiampo Valley Stone Association www.porfido.it E.S.P.O. Institute for the development of Porfido www.videomarmoteca.it Research Lab on stone materials of Volargne VR www.fepa-abrasives.com Fepa norms www.astm.org American Society for Testing and Materials, normative tecniche ASTM www.iso.ch International Standard Organisation Normative ISO www.uni.com Italian normative institute