1. Rasberry SD, Gills TE (1991) Spectrochim Acta 46B:1577?1582
2. ISO Guide 35 (1985) Certification of reference materials. General and statistical principles. ISO, Gen�ve, Switzerland
3. Klich H (1994) Sixth International Symposium on Biological and Environmental Reference Materials, Kailua-Kona, Hawaii (abstract)
4. ISO Guide 31 (1981) Contents of certificates of reference materials. ISO, Gen�ve, Switzerland
5. ISO Guide 34 (draft) (1993) Quality System requirements for the production of reference materials. ISO/REMCO N 282 Rev., ISO, Gen�ve, Switzerland