LGC Promochem is Europe’s most comprehensive source of reference materials.
http://www.lgcpromochem.com

NIST supplies industry, academia, government, and other users with over 1100 reference materials of the highest quality and metrological value.
http://www.nist.gov

The sole officially recognised Certificated Reference Material produced from Canada.
http://inms-ienm.nrc-cnrc.gc.ca

Providing Certified Reference Materials and QA services for water and sediment trace elements.
http://www.ec.gc.ca/inre-nwri/