1. W. Wälchli and P. Vuilleumier, ‘Assaying Gold by Cupellation’,Aurum, 1987(No. 29), 56–64;Gold Technology, 1991 (No. 3), 19–27.
2. International Organization for Standardization, Doc. ISO/TC 174 N87, June 1988
3. International Organization for Standardization, Doc. ISO/TC 174 N50, June 1988
4. International Organization for Standardization, Doc. ISO/TC 174 WG 1 N 71, Milano, Oct. 1989
5. M. Brill, ‘Bericht über das Geschäftsjahr 1988’, Fachvereinigung Edelmetalle e.V. Düsseldorf, pp. 63–84 (1989)