B. Guinot, P. K. Seidelmann (April 1988). "Time scales - Their history, definition and interpretation". Astronomy and Astrophysics. 194 (1–2): 304–308. Bibcode:1988A&A...194..304G. at p.304 /wiki/Bibcode_(identifier)
P.K.Seidelmann, ed. (1992). Explanatory Supplement to the Astronomical Almanac. CA: University Science Books. 41. ISBN 0-935702-68-7. 0-935702-68-7
W Markowitz, 'Variations in the Rotation of the Earth, Results Obtained with the Dual-Rate Moon Camera and Photographic Zenith Tubes', Astron J v64 (1959) 106-113. http://adsabs.harvard.edu/full/1959AJ.....64..106M
B. Guinot, P. K. Seidelmann (April 1988). "Time scales - Their history, definition and interpretation". Astronomy and Astrophysics. 194 (1–2): 304–308. Bibcode:1988A&A...194..304G. at p.304 /wiki/Bibcode_(identifier)
See S Klioner et al., "Units of relativistic time scales and associated quantities", IAU Symposium 261 (2009).
IAU 2000 resolutions, at Resolution B1.9. http://syrte.obspm.fr/IAU_resolutions/Resol-UAI.rtf