Internationally, the London Bullion Market Association accepts the assay mark of sixty refineries in twenty-eight countries on its good delivery list for gold, together with forty-two former melters and assayers. Registration of assayers and marks varies from one country to another. In France, the assay stamps recognised are those registered by individual assayers with the Chambre Syndicale des Agents de Change. In Switzerland, assayers must be approved by Bureau Central du Controle Métaux Précieux.