Reference Standard Sources

Analytical Reference Materials International
 http://www.armi.com/

ASTM; International - Standards Worldwide
 http://www.astm.org/cgi-bin/SoftCart.exe/index.shtml?E+mystore

BAM (German)
 http://www.bam.de/

Brammer Standard
 http://www.brammerstandard.com/default.htm

CEN - European Committee for Standardization 
http://www.cen.eu/cenorm/homepage.htm

Chemical Metrology - Client Services | NRC-INMS
 http://inms-ienm.nrc-cnrc.gc.ca/calserv/chemical_metrology_e.html#Certified 

COMAR Database for Certified Reference Materials
 http://www.comar.bam.de/

Institute for National Measurement Standards
 http://inms-ienm.nrc-cnrc.gc.ca/

Institute for Reference Materials and Measurements
 http://www.irmm.jrc.be/html/reference_materials_catalogue/catalogue/index.htm

International Association of Geoanalysts
 http://geoanalyst.org/

International Center for Diffraction Data https://www.dxcicdd.com/

International Organization for Standardization
 http://www.iso.org/iso/home.htm

NIST: National Institute of Standards and Technology 
http://ts.nist.gov/measurementservices/referencematerials/index.cfm