* ISO 4531-1, July 2003, Vitreous and porcelain enamels -- Release of lead and cadmium from enamelled ware in contact with food -- Part 1: Method of test
* ISO 4531-2, July 2003, Vitreous and porcelain enamels -- Release of lead and cadmium from enamelled ware in contact with food -- Part 2: Permissible limits