{{el}} http://www.ngs.noaa.gov/PUBS_LIB/FedRegister/FRdoc59-5442.pdf <!-- da:U.S. National Institute of Standards and Technology Official Definition, showing history da->eo:U.S. _National_ _Institute_ _of_ _Standards_ _and_ _Technology_ _Official_ Difino, _showing_ _history_ -->
{{el}} http://physics.nist.gov/Pubs/SP811/appenB9.html#MASSinertia <!-- da:U.S. National Institute of Standards and Technology Special Publication 811 da->eo:U.S. _National_ _Institute_ _of_ _Standards_ _and_ _Technology_ _Special_ _Publication_ 811 -->