[1] European Commission, Joint Research Centre, Institute for Reference Materials and Measurements (IRMM), 2440 Geel
[2] Quality Analysis Consultants, Winnipeg, MB
[3] Merieux NutriSciences Corporation, Chicago, IL
[4] Analytical Chemistry Division, National Institute of Standards and Technology, Gaithersburg, MD
[5] AIM Research Enterprises LLC, Carthage, MO