Other links

•	National Metrology Centre (NMC)
	http://www.nmc.a-star.edu.sg
•	Bureau International des Poids et Measures (BIPM)
	http://www.bipm.org
•	International Earth Rotation and Reference Systems Service (IERS)
	http://www.iers.org
•	International GNSS Service (IGS)
	http://igscb.jpl.nasa.gov