W.
L.
Tew
Nicholson, T. L., Campbell, S. L., Hutson, R. B., Marti, G. E., Bloom, B. J., McNally, R. L., … Ye, J. . (2015). Systematic evaluation of an atomic clock at 2 x 10 (-18) total uncertainty. Nature Communications, 6. http://doi.org/10.1038/ncomms7896