1. INRIM, Torino, Italy
2. Hannam University, Daejeon, Korea
3. PTB, Braunschweig, Germany
4. TU Wien, Austria
5. IMEM-CNR, Parma, Italy
6. China Jiliang University, Hangzhou, Zhejiang, China
7. NIM, Bejing, China
8. INCDIE ICPE-CA, Bucharest, Romania
9. NIST, Gaithersburg, MD, USA
10. NPL, Teddington, UK