Time & Frequency and Measurement in General

Time and Frequency at NIST

NIST

Time and Frequency at NPL

NPL

MSF at NPL

MSF

Rugby MSF visit

Rugby MSF visit at Subterranea Britannica

Fundamental Constants

Fundamental Constants

SI

The International System of Units

SP330 (html)
SP330 (pdf)

Guide for the Use of the International System of Units

This next document gives an excellent description of what to write and what not to write.

Remember to

SP811 (html)
SP811 (pdf)
ISO 31

ISO 8601 time and notation

ISO time from Wikipedia
A Summary of the International Standard Date and Time Notation